Method and apparatus for transmitting uplink control information in a wireless communication system

ABSTRACT

The present invention provides a method and apparatus for transmitting uplink control information (UCI) with user equipment in a wireless communication system. The user equipment performs channel coding on information bits of UCI to generate encoded information bits; modulates the generated encoded information bits to generate complex modulation symbols; spreads the complex modulation symbols blockwise into a plurality of single carrier frequency division multiple access (SC-FDMA) symbols on the basis of an orthogonal sequence; and transmits the spread complex modulation symbols to a base station.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to wireless communication, andspecifically, the present invention relates to a method and an apparatusfor transmitting uplink control information by a user equipment in awireless communication system.

2. Related Art

Effective transmission/reception methods and utilizations have beenproposed for a broadband wireless communication system to maximizeefficiency of radio resources. An orthogonal frequency divisionmultiplexing (OFDM) system capable of reducing inter-symbol interference(ISI) with a low complexity is taken into consideration as one of nextgeneration wireless communication systems. In the OFDM, a serially inputdata symbol is converted into N parallel data symbols, and is thentransmitted by being carried on each of separated N subcarriers. Thesubcarriers maintain orthogonality in a frequency dimension. Eachorthogonal channel experiences mutually independent frequency selectivefading, and an interval of a transmitted symbol is increased, therebyminimizing inter-symbol interference.

When a system uses the OFDM as a modulation scheme, orthogonal frequencydivision multiple access (OFDMA) is a multiple access scheme in whichmultiple access is achieved by independently providing some of availablesubcarriers to a plurality of users. In the OFDMA, frequency resources(i.e., subcarriers) are provided to the respective users, and therespective frequency resources do not overlap with one another ingeneral since they are independently provided to the plurality of users.Consequently, the frequency resources are allocated to the respectiveusers in a mutually exclusive manner. In an OFDMA system, frequencydiversity for multiple users can be obtained by using frequencyselective scheduling, and subcarriers can be allocated variouslyaccording to a permutation rule for the subcarriers. In addition, aspatial multiplexing scheme using multiple antennas can be used toincrease efficiency of a spatial domain.

MIMO technology can be used to improve the efficiency of datatransmission and reception using multiple transmission antennas andmultiple reception antennas. MIMO technology may include a spacefrequency block code (SFBC), a space time block code (STBC), a cyclicdelay diversity (CDD), a frequency switched transmit diversity (FSTD), atime switched transmit diversity (TSTD), a precoding vector switching(PVS), spatial multiplexing (SM) for implementing diversity. An MIMOchannel matrix according to the number of reception antennas and thenumber of transmission antennas can be decomposed into a number ofindependent channels. Each of the independent channels is called a layeror stream. The number of layers is called a rank.

Uplink control information (UCI) can be transmitted through a physicaluplink control channel (PUCCH). The UCI can include various types ofinformation such as a scheduling request (SR), anacknowledgement/non-acknowledgement (ACK/NACK) signal for hybrid ARQ(HARQ), a channel quality indicator (CQI), a precoding matrix indicator(PMI), a rank indicator (RI), etc. The PUCCH carries various types ofcontrol information according to a format.

There is a need for a method for effectively transmitting various typesof UCI.

SUMMARY OF THE INVENTION

The present invention provides a method and an apparatus fortransmitting uplink control information by a user equipment in awireless communication system.

In an aspect, a method for transmitting uplink control information (UCI)by a user equipment in a wireless communication system is provided. Themethod includes performing channel coding on information bits of the UCIto generate encoding information bits, modulating the generated encodinginformation bits to generate complex modulation symbols, block-wisespreading the complex modulation symbols to multiple singlecarrier-frequency division multiple access (SC-FDMA) symbols on thebasis of an orthogonal sequence, and transmitting the spread complexmodulation symbols to a base station.

The information bits of the UCI may include concatenation of a hybridautomatic repeat request (HARQ)-acknowledgement (ACK) information bitfor each cell.

The HARQ-ACK information bit for each cell may be determined based on atransmission mode of each cell.

If the transmission mode of each cell is a single codeword transmissionmode, the HARQ-ACK information bit for each cell may be 1 bit.

If the transmission mode of each cell is not a single codewordtransmission mode, the HARQ-ACK information bit for each cell may be 2bits.

From the two HARQ-ACK information bits for each cell, one bit mayindicate HARQ-ACK information on a first codeword and the other bit mayindicate HARQ-ACK information on a second codeword.

The generating the encoding information bits comprises obtaining a stateinformation bit indicating state information of each of a plurality ofconfigured cells, generating a synthesized state information bit streamby combining the state information bit of each of the plurality ofconfigured cells, and encoding the synthesized state information bitstream into a binary stream.

A length of the binary stream may be determined based on a number of theplurality of configured cells given by a radio resource control (RRC)signaling.

State information of each of the plurality of configured cells may bemapped to a predetermined state index.

A position of state information bit of each of the plurality ofconfigured cells in the binary stream may be pre-determined.

State information bit of the configured cell which fails to decode aphysical downlink control channel (PDCCH) may be set to 0.

In another aspect, a user equipment in a wireless communication systemis provided. The user equipment includes a radio frequency (RF) unit fortransmitting or receiving a radio signal, and a processor connected tothe RF unit, and configured for performing channel coding on informationbits of the UCI to generate encoding information bits, modulating thegenerated encoding information bits to generate complex modulationsymbols, block-wise spreading the complex modulation symbols to multiplesingle carrier-frequency division multiple access (SC-FDMA) symbols onthe basis of an orthogonal sequence.

In another aspect, a method for decoding uplink control information(UCI) in a wireless communication system is provided. The methodincludes obtaining a binary stream for which channel decoding has beencarried out, decoding the obtained binary stream into synthesized stateinformation, and obtaining state information of each configured cellfrom the synthesized state information.

A size of codebook required for a hybrid automatic repeat request(HARQ)-acknowledgement (ACK) can be determined based on the number ofconfigured cells and a transmission mode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a wireless communication system.

FIG. 2 shows the structure of a radio frame in 3GPP LTE.

FIG. 3 shows an example of a resource grid of a single downlink slot.

FIG. 4 shows the structure of a downlink subframe.

FIG. 5 shows the structure of an uplink subframe.

FIG. 6 shows a PUCCH format 1a/1b in a normal CP structure.

FIG. 7 shows a PUCCH format 1a/1b in an extended CP structure.

FIG. 8 shows a PUCCH format 2/2a/2b.

FIG. 9 shows an example of the structure of a transmitter in an SC-FDMAsystem.

FIG. 10 shows an example of a scheme in which the subcarrier mapper mapsthe complex-valued symbols to the respective subcarriers of thefrequency domain.

FIG. 11 shows an example of a transmitter using the clustered DFT-s OFDMtransmission scheme.

FIG. 12 shows another example of a transmitter using the clustered DFT-sOFDM transmission scheme.

FIG. 13 shows another example of a transmitter using the clustered DFT-sOFDM transmission scheme.

FIG. 14 shows an example of a transmitter and a receiver whichconstitute a carrier aggregation system.

FIGS. 15 and 16 show another example of a transmitter and a receiverwhich constitute a carrier aggregation system.

FIG. 17 illustrates three entities.

FIG. 18 illustrates a plurality of entities.

FIG. 19 is an example of a method for transmitting feedback informationaccording to an embodiment of the present invention.

FIG. 20 is an example of a method for encoding uplink controlinformation carried out by a state-bit encoder according to anembodiment of the present invention.

FIG. 21 is an example of a method for receiving feedback informationwhen the corresponding feedback information is transmitted by a methodfor encoding uplink control information according to an embodiment ofthe present invention.

FIG. 22 is an example of a method for decoding uplink controlinformation carried out by a state-bit decoder according to anembodiment of the present invention.

FIG. 23 is a block diagram illustrating a case where one UL CCcorresponds to five DL CCs in a carrier aggregation system.

FIG. 24 is an example of an extended PUCCH format.

FIG. 25 is another example of an extended PUCCH format.

FIG. 26 shows an example of time spreading for a modulated QPSK symbolwith an extended PUCCH format.

FIG. 27 is another example of time spreading for a modulated QPSK symbolwith an extended PUCCH format.

FIG. 28 is another example of an extended PUCCH format.

FIG. 29 is a block diagram of a base station and a terminal for which anembodiment of the present invention is implemented.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following technique may be used for various wireless communicationsystems such as code division multiple access (CDMA), a frequencydivision multiple access (FDMA), time division multiple access (TDMA),orthogonal frequency division multiple access (OFDMA), singlecarrier-frequency division multiple access (SC-FDMA), and the like. TheCDMA may be implemented as a radio technology such as universalterrestrial radio access (UTRA) or CDMA2000. The TDMA may be implementedas a radio technology such as a global system for mobile communications(GSM)/general packet radio service (GPRS)/enhanced data rates for GSMevolution (EDGE). The OFDMA may be implemented by a radio technologysuch as institute of electrical and electronics engineers (IEEE) 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, E-UTRA (evolved UTRA), andthe like. IEEE 802.16m, an evolution of IEEE 802.16e, provides backwardcompatibility with a system based on IEEE 802.16e. The UTRA is part of auniversal mobile telecommunications system (UMTS). 3GPP (3rd generationpartnership project) LTE (long term evolution) is part of an evolvedUMTS (E-UMTS) using the E-UTRA, which employs the OFDMA in downlink andthe SC-FDMA in uplink. LTE-A (advanced) is an evolution of 3GPP LTE.

Hereinafter, for clarification, LTE-A will be largely described, but thetechnical concept of the present invention is not meant to be limitedthereto.

FIG. 1 shows a wireless communication system.

The wireless communication system 10 includes at least one base station(BS) 11. Respective BSs 11 provide a communication service to particulargeographical areas 15 a, 15 b, and 15 c (which are generally calledcells). Each cell may be divided into a plurality of areas (which arecalled sectors). A user equipment (UE) 12 may be fixed or mobile and maybe referred to by other names such as MS (mobile station), MT (mobileterminal), UT (user terminal), SS (subscriber station), wireless device,PDA (personal digital assistant), wireless modem, handheld device. TheBS 11 generally refers to a fixed station that communicates with the UE12 and may be called by other names such as eNB (evolved-NodeB), BTS(base transceiver system), access point (AP), etc.

In general, a UE belongs to one cell, and the cell to which a UE belongsis called a serving cell. A BS providing a communication service to theserving cell is called a serving BS. The wireless communication systemis a cellular system, so a different cell adjacent to the serving cellexists. The different cell adjacent to the serving cell is called aneighbor cell. A BS providing a communication service to the neighborcell is called a neighbor BS. The serving cell and the neighbor cell arerelatively determined based on a UE.

This technique can be used for downlink or uplink. In general, downlinkrefers to communication from the BS 11 to the UE 12, and uplink refersto communication from the UE 12 to the BS 11. In downlink, a transmittermay be part of the BS 11 and a receiver may be part of the UE 12. Inuplink, a transmitter may be part of the UE 12 and a receiver may bepart of the BS 11.

The wireless communication system may be any one of a multiple-inputmultiple-output (MIMO) system, a multiple-input single-output (MISO)system, a single-input single-output (SISO) system, and a single-inputmultiple-output (SIMO) system. The MIMO system uses a plurality oftransmission antennas and a plurality of reception antennas. The MISOsystem uses a plurality of transmission antennas and a single receptionantenna. The SISO system uses a single transmission antenna and a singlereception antenna. The SIMO system uses a single transmission antennaand a plurality of reception antennas. Hereinafter, a transmissionantenna refers to a physical or logical antenna used for transmitting asignal or a stream, and a reception antenna refers to a physical orlogical antenna used for receiving a signal or a stream.

FIG. 2 shows the structure of a radio frame in 3GPP LTE.

It may be referred to Paragraph 5 of “Technical Specification GroupRadio Access Network; Evolved Universal Terrestrial Radio Access(E-UTRA); Physical channels and modulation (Release 8)” to 3GPP (3rdgeneration partnership project) TS 36.211 V8.2.0 (2008-03). Referring toFIG. 2, the radio frame includes 10 subframes, and one subframe includestwo slots. The slots in the radio frame are numbered by #0 to #19. Atime taken for transmitting one subframe is called a transmission timeinterval (TTI). The TTI may be a scheduling unit for a datatransmission. For example, a radio frame may have a length of 10 ms, asubframe may have a length of 1 ms, and a slot may have a length of 0.5ms.

One slot includes a plurality of orthogonal frequency divisionmultiplexing (OFDM) symbols in a time domain and a plurality ofsubcarriers in a frequency domain. Since 3GPP LTE uses OFDMA indownlink, the OFDM symbols are used to express a symbol period. The OFDMsymbols may be called by other names depending on a multiple-accessscheme. For example, when a single carrier frequency division multipleaccess (SC-FDMA) is in use as an uplink multi-access scheme, the OFDMsymbols may be called SC-FDMA symbols. A resource block (RB), a resourceallocation unit, includes a plurality of continuous subcarriers in aslot. The structure of the radio frame is merely an example. Namely, thenumber of subframes included in a radio frame, the number of slotsincluded in a subframe, or the number of OFDM symbols included in a slotmay vary.

3GPP LTE defines that one slot includes seven OFDM symbols in a normalcyclic prefix (CP) and one slot includes six OFDM symbols in an extendedCP.

The wireless communication system may be divided into a frequencydivision duplex (FDD) scheme and a time division duplex (TDD) scheme.According to the FDD scheme, an uplink transmission and a downlinktransmission are made at different frequency bands. According to the TDDscheme, an uplink transmission and a downlink transmission are madeduring different periods of time at the same frequency band. A channelresponse of the TDD scheme is substantially reciprocal. This means thata downlink channel response and an uplink channel response are almostthe same in a given frequency band. Thus, the TDD-based wirelesscommunication system is advantageous in that the downlink channelresponse can be obtained from the uplink channel response. In the TDDscheme, the entire frequency band is time-divided for uplink anddownlink transmissions, so a downlink transmission by the BS and anuplink transmission by the UE can be simultaneously performed. In a TDDsystem in which an uplink transmission and a downlink transmission arediscriminated in units of subframes, the uplink transmission and thedownlink transmission are performed in different subframes.

FIG. 3 shows an example of a resource grid of a single downlink slot.

A downlink slot includes a plurality of OFDM symbols in the time domainand N_(RB) number of resource blocks (RBs) in the frequency domain. TheN_(RB) number of resource blocks included in the downlink slot isdependent upon a downlink transmission bandwidth set in a cell. Forexample, in an LTE system, N_(RB) may be any one of 60 to 110. Oneresource block includes a plurality of subcarriers in the frequencydomain. An uplink slot may have the same structure as that of thedownlink slot.

Each element on the resource grid is called a resource element. Theresource elements on the resource grid can be discriminated by a pair ofindexes (k,l) in the slot. Here, k (k=0, . . . , N_(RB)×12−1) is asubcarrier index in the frequency domain, and 1 is an OFDM symbol indexin the time domain.

Here, it is illustrated that one resource block includes 7×12 resourceelements made up of seven OFDM symbols in the time domain and twelvesubcarriers in the frequency domain, but the number of OFDM symbols andthe number of subcarriers in the resource block are not limited thereto.The number of OFDM symbols and the number of subcarriers may varydepending on the length of a cyclic prefix (CP), frequency spacing, andthe like. For example, in case of a normal CP, the number of OFDMsymbols is 7, and in case of an extended CP, the number of OFDM symbolsis 6. One of 128, 256, 512, 1024, 1536, and 2048 may be selectively usedas the number of subcarriers in one OFDM symbol.

FIG. 4 shows the structure of a downlink subframe.

A downlink subframe includes two slots in the time domain, and each ofthe slots includes seven OFDM symbols in the normal CP. First three OFDMsymbols (maximum four OFDM symbols with respect to a 1.4 MHz bandwidth)of a first slot in the subframe corresponds to a control region to whichcontrol channels are allocated, and the other remaining OFDM symbolscorrespond to a data region to which a physical downlink shared channel(PDSCH) is allocated.

The PDCCH may carry a transmission format and a resource allocation of adownlink shared channel (DL-SCH), resource allocation information of anuplink shared channel (UL-SCH), paging information on a PCH, systeminformation on a DL-SCH, a resource allocation of an higher layercontrol message such as a random access response transmitted via aPDSCH, a set of transmission power control commands with respect toindividual UEs in a certain UE group, an activation of a voice overinternet protocol (VoIP), and the like. A plurality of PDCCHs may betransmitted in the control region, and a UE can monitor a plurality ofPDCCHs. The PDCCHs are transmitted on one or an aggregation of aplurality of consecutive control channel elements (CCE). The CCE is alogical allocation unit used to provide a coding rate according to thestate of a wireless channel. The CCE corresponds to a plurality ofresource element groups. The format of the PDCCH and an available numberof bits of the PDCCH are determined according to an associative relationbetween the number of the CCEs and a coding rate provided by the CCEs.

The BS determines a PDCCH format according to a DCI to be transmitted tothe UE, and attaches a cyclic redundancy check (CRC) to the DCI. Aunique radio network temporary identifier (RNTI) is masked on the CRCaccording to the owner or the purpose of the PDCCH. In case of a PDCCHfor a particular UE, a unique identifier, e.g., a cell-RNTI (C-RNTI), ofthe UE, may be masked on the CRC. Or, in case of a PDCCH for a pagingmessage, a paging indication identifier, e.g., a paging-RNTI (P-RNTI),may be masked on the CRC. In case of a PDCCH for a system informationblock (SIB), a system information identifier, e.g., a systeminformation-RNTI (SI-RNTI), may be masked on the CRC. In order toindicate a random access response, i.e., a response to a transmission ofa random access preamble of the UE, a random access-RNTI (RA-RNTI) maybe masked on the CRC.

FIG. 5 shows the structure of an uplink subframe.

An uplink subframe may be divided into a control region and a dataregion in the frequency domain. A physical uplink control channel(PUCCH) for transmitting uplink control information is allocated to thecontrol region. A physical uplink shared channel (PUCCH) fortransmitting data is allocated to the data region.

The PUSCH is mapped to a uplink shared channel (UL-SCH), a transportchannel. Uplink data transmitted on the PUSCH may be a transport block,a data block for the UL-SCH transmitted during the TTI. The transportblock may be user information. Or, the uplink data may be multiplexeddata. The multiplexed data may be data obtained by multiplexing thetransport block for the UL-SCH and control information. For example,control information multiplexed to data may include a CQI, a precodingmatrix indicator (PMI), an HARQ, a rank indicator (RI), or the like. Orthe uplink data may include only control information.

The following description is about a PUCCH.

The PUCCH for one UE is allocated in an RB pair. RBs belonging to the RBpair occupy different subcarriers in each of a 1^(st) slot and a 2^(nd)slot. A frequency occupied by the RBs belonging to the RB pair allocatedto the PUCCH changes at a slot boundary. This is called that the RB pairallocated to the PUCCH is frequency-hopped at a slot boundary. Since theUE transmits UL control information over time through differentsubcarriers, a frequency diversity gain can be obtained. In the figure,m is a location index indicating a logical frequency-domain location ofthe RB pair allocated to the PUCCH in the subframe.

The PUCCH carries various types of control information according to aformat. A PUCCH format 1 carries a scheduling request (SR). In thiscase, an on-off keying (OOK) scheme can be used. A PUCCH format 1acarries an acknowledgement/non-acknowledgement (ACK/NACK) modulated byusing bit phase shift keying (BPSK) with respect to one codeword. APUCCH format 1b carries an ACK/NACK modulated by using quadrature phaseshift keying (QPSK) with respect to two codewords. A PUCCH format 2carries a channel quality indicator (CQI) modulated by using QPSK. PUCCHformats 2a and 2b carry CQI and ACK/NACK.

Table 1 shows a modulation scheme and the number of bits in a subframeaccording to a PUCCH format.

TABLE 1 Number of bits per PUCCH format Modulation scheme sub frame,M_(bit) 1 N/A N/A 1a BPSK 1 1b QPSK 2 2 QPSK 20 2a QPSK + BPSK 21 2bQPSK + QPSK 22

Table 2 shows the number of OFDM symbols used as a PUCCH demodulationreference signal per slot.

TABLE 2 PUCCH format Normal cyclic prefix Extended cyclic prefix 1, 1a,1b 3 2 2 2 1 2a, 2b 2 N/A

Table 3 shows a position of an OFDM symbol to which a demodulationreference signal is mapped according to a PUCCH format.

TABLE 3 set of values for l PUCCH format Normal cyclic prefix Extendedcyclic prefix 1, 1a, 1b 2, 3, 4 2, 3 2, 2a, 2b 1, 5 3

ACK/NACK signals can be transmitted by using different resourcesincluding different cyclic shift values and different Walsh/discreteFourier transform (DFT) orthogonal codes by using a computer generatedconstant amplitude zero auto correlation (CG-CAZAC) sequence for eachUE. If an available cyclic shift value is 6 and the number of Walsh/DFTcodes is 3, 18 UEs having a signal antenna port can be multiplexed inone PRB.

FIG. 6 shows a PUCCH format 1a/1b in a normal CP structure. Uplinkreference signals are transmitted in 3^(rd) to 5^(th) SC-FDMA symbols.In FIG. 6, w₀, w₁, w₂ and w₃ can be modulated in a time domain afterinverse fast Fourier transform (IFFT) modulation, or can be modulated ina frequency domain before IFFT modulation.

FIG. 7 shows a PUCCH format 1a/1b in an extended CP structure. Uplinkreference signals are transmitted in 3^(rd) and 4^(th) SC-FDMA symbols.In FIG. 7, w₀, w₁, w₂ and w₃ can be modulated in a time domain afterIFFT modulation, or can be modulated in a frequency domain before IFFTmodulation.

An ACK/NACK resource including an SR, a cyclic shift assigned to the UEfor persistent scheduling, a Walsh/DFT code, a PRB, or the like can begiven by using RRC signaling. For non-persistent scheduling for dynamicACK/NACK, the allocated resource can be given by a lowest CCE index of aPDCCH corresponding to a PDSCH for the ACK/NACK.

Table 4 is an example of an orthogonal sequence with a length of 4 forthe PUCCH format 1/1a/1b.

TABLE 4 Sequence Orthogonal sequences index n_(oc)(n_(s)) [w(0) . . .w(N_(SF) ^(PUCCH) − 1)] 0 [+1 +1 +1 +1] 1 [+1 −1 +1 −1] 2 [+1 −1 −1 +1]

Table 5 is an example of an orthogonal sequence with a length of 3 forthe PUCCH format 1/1a/1b.

TABLE 5 Sequence Orthogonal sequences index n_(oc)(n_(s)) [w(0) . . .w(N_(SF) ^(PUCCH) − 1)] 0 [1 1 1] 1 [1 e^(j2π/3) e^(j4π/3)] 2 [1e^(j4π/3) e^(j2π/3)]

Table 6 is an example of an orthogonal sequence for reference signaltransmission in the PUCCH format 1/1a/1b.

TABLE 6 Sequence index n_(oc2)(n_(s)) Normal cyclic prefix Extendedcyclic prefix 0 [1 1 1] [1 1]  1 [1 e^(j2π/3) e^(j4π/3)] [1 −1] 2 [1e^(j4π/3) e^(j2π/3)] N/A

Table 7 is an example of ACK/NACK channelization when Δ_(shift)^(PUCCH)=2 in a normal CP structure.

TABLE 7 Cell specific cyclic RS orthogonal ACK/NACK orthogonal shiftoffset cover cover δ_(offset) ^(PUCCH) = 1 δ_(offset) ^(PUCCH) = 0n_(OC)′ = 0 n_(OC)′ = 1 n_(OC)′ = 2 n_(OC) = 0 n_(OC) = 1 n_(OC) = 2n_(CS) = 1 n_(CS) = 0 n′ = 0 12 n′ = 0 12 2 1 6 6 3 2 1 13 1 13 4 3 7 75 4 2 14 2 14 6 5 8 8 7 6 3 15 3 15 8 7 9 9 9 8 4 16 4 16 10 9 10 10 1110 5 17 5 17 0 11 11 11

In Table 7, Δ_(shift) ^(PUCCH) is a cell-specific cyclic shift value ofa CAZAC sequence, and may have any one of values 1 to 3 in a normal CPstructure or an extended CP structure. δ_(offset) ^(PUCCH) is acell-specific cyclic shift offset, and may have any one of values 0 toΔ_(shift) ^(PUCCH)−1. Meanwhile, n_(OC) is an index of an orthogonalsequence for ACK/NACK, and n_(OC)′ is an index of an orthogonal sequencefor a reference signal. n_(CS) is a cyclic shift value of a CAZACsequence, and n′ is an ACK/NACK resource index used for channelizationin an RB.

Table 8 is an example of channelization of a structure in which a PUCCHformat 1/1a/1b and a PUCCH format 2/2a/2b are mixed in a PRB.

TABLE 8 Cyclic Orthogonal cover Shift OC_(index) = 0 OC_(index) = 1OC_(index) = 2 0 ACK/NACK 1 ACK/NACK 2 ACK/NACK 3 ACK/NACK 4 Guardshifts 5 CQI 6 CQI 7 CQI 8 CQI 9 CQI 10 CQI 11 Guard shifts

Referring to Table 8, cyclic shift values 0 to 3 for the PUCCH format1/1a/1b are allocated, and cyclic shift values 5 to 10 for the PUCCHformat 2/2a/2b are allocated. Cyclic shift values 4 and 11 between thePUCCH format 1/1a/1b and the PUCCH format 2/2a/2b are allocated as aguard shift.

Meanwhile, cyclic shift hopping can be performed on a symbol basis forinter-cell interference (ICI) randomization. In addition, for the ICIrandomization, CS/orthogonal covering (OC) remapping can be performedbetween an ACK/NACK channel and a resource in a slot level.

A resource for the PUCCH format 1/1a/1b can consist of n_(CS) indicatinga cyclic shift in a symbol level, n_(OC) indicating orthogonal coveringin a slot level, and n_(RB) indicating a resource block in a frequencydomain. n_(r) can be defined as an index representing the PUCCH format1/1a/1b resources n_(CS), n_(OC), n_(RB). That is,n_(r)=(n_(cs),n_(oc),n_(RB)).

The PUCCH format 2/2a/2b can carry control information such as a CQI, aprecoding matrix indicator (PMI), a rank indicator (RI), CQI+ACK/NACK,etc. A Reed-Muller (RM) channel coding scheme can be applied to thePUCCH format 2/2a/2b.

Table 9 shows an example of a (20,A) RM code used in channel coding ofuplink control information (UCI) of 3GPP LTE. A bit-stream a₀, a₁, a₂, .. . , a_(A-1) is used as an input of a channel coding block using the(20,A) RM code of Table 9.

TABLE 9 i M_(i, 0) M_(i, 1) M_(i, 2) M_(i, 3) M_(i, 4) M_(i, 5) M_(i, 6)M_(i, 7) M_(i, 8) M_(i, 9) M_(i, 10) M_(i, 11) M_(i, 12) 0 1 1 0 0 0 0 00 0 0 1 1 0 1 1 1 1 0 0 0 0 0 0 1 1 1 0 2 1 0 0 1 0 0 1 0 1 1 1 1 1 3 10 1 1 0 0 0 0 1 0 1 1 1 4 1 1 1 1 0 0 0 1 0 0 1 1 1 5 1 1 0 0 1 0 1 1 10 1 1 1 6 1 0 1 0 1 0 1 0 1 1 1 1 1 7 1 0 0 1 1 0 0 1 1 0 1 1 1 8 1 1 01 1 0 0 1 0 1 1 1 1 9 1 0 1 1 1 0 1 0 0 1 1 1 1 10 1 0 1 0 0 1 1 1 0 1 11 1 11 1 1 1 0 0 1 1 0 1 0 1 1 1 12 1 0 0 1 0 1 0 1 1 1 1 1 1 13 1 1 0 10 1 0 1 0 1 1 1 1 14 1 0 0 0 1 1 0 1 0 0 1 0 1 15 1 1 0 0 1 1 1 1 0 1 10 1 16 1 1 1 0 1 1 1 0 0 1 0 1 1 17 1 0 0 1 1 1 0 0 1 0 0 1 1 18 1 1 0 11 1 1 1 0 0 0 0 0 19 1 0 0 0 0 1 1 0 0 0 0 0 0

Channel encoding bits b₀, b₁, b₂, . . . , b_(B-1) can be generated byEquation 1 below.

$\begin{matrix}{b_{i} = {\sum\limits_{n = 0}^{A - 1}\; {\left( {a_{n} \cdot M_{i,n}} \right){mod}\mspace{11mu} 2}}} & {< {{Equation}\mspace{14mu} 1} >}\end{matrix}$

In Equation 1, i=0, 1, 2, . . . , B−1.

Table 10 shows an example of a size of a CQI feedback UCI field forwideband reporting. Table 11 is a case where a single-antenna port isassumed, and transmit diversity or open-loop spatial multiplexing PDSCHtransmission is assumed.

TABLE 10 Field Bitwidth Wide-band CQI 4

Table 11 is an example of a CQI and PMI feedback UCI field for widebandreporting. Table 11 is a case of closed-loop spatial multiplexing PDSCHtransmission.

TABLE 11 Bitwidths 2 antenna ports 4 antenna ports Field Rank = 1 Rank =2 Rank = 1 Rank >1 Wide-band CQI 4 4 4 4 Spatial differential CQI 0 3 03 Precoding matrix 2 1 4 4 indication

Table 12 is an example of a size of an RI feedback UCI field forwideband reporting.

TABLE 12 Bitwidths 4 antenna ports Field 2 antenna ports Max 2 layersMax 4 layers Rank indication 1 1 2

In this case, a₀ and a_(A-1) respectively denote a most significant bit(MSB) and a least significant bit (LSB). In the extended CP structure, Acan be up to 11 except for a case where CQI and ACK/NACK aresimultaneously transmitted. QPSK modulation can be applied to controlinformation encoded into 20 bits by using an RM code. In addition, theencoded control information can be scrambled before QPSK modulation.

FIG. 8 shows a PUCCH format 2/2a/2b. FIG. 8( a) shows a normal CPstructure, and FIG. 8( b) shows an extended CP structure. In FIG. 8( a),reference signals are transmitted in 2^(nd) and 6^(th) SC-FDMA symbols.In FIG. 8( b), reference signals are transmitted in a 4^(th) SC-FDMAsymbol.

In a normal CP structure, one subframe includes 10 QPSK data symbolsexcept for an SC-FDMA symbol for reference signal transmission. That is,each QPSK symbol can be spread by a cyclic shift in an SC-FDMA symbollevel by using a 20-bit encoded CQI.

In addition, SC-FDMA symbol level cyclic shift hopping can be appliedfor ICI randomization. A reference signal can be multiplexed accordingto code division multiplexing (CDM) by using a cyclic shift. Forexample, if the number of available cyclic shift values is 12, 12 UEscan be multiplexed in one PRB. That is, each of a plurality of UEs in aPUCCH format 1/1a/1b and a PUCCH format 2/2a/2b can be multiplexed byusing a cyclic shift/orthogonal covering/resource block and a cyclicshift/resource block.

A PRB used for PUCCH transmission in a slot n_(s) can be determined byEquation 2.

$\begin{matrix}{n_{PRB} = \left\{ \begin{matrix}\left\lfloor \frac{m}{2} \right\rfloor & {{{if}\mspace{14mu} \left( {m + {n_{s}\mspace{11mu} {mod}\mspace{11mu} 2}} \right){mod}\mspace{11mu} 2} = 0} \\{N_{RB}^{UL} - 1 - \left\lfloor \frac{m}{2} \right\rfloor} & {{{if}\mspace{14mu} \left( {m + {n_{s}\mspace{11mu} {mod}\mspace{11mu} 2}} \right){mod}\mspace{11mu} 2} = 1}\end{matrix} \right.} & {< {{Equation}\mspace{14mu} 2} >}\end{matrix}$

In Equation 2, n_(PRB) denotes a PRB index. N_(RB) ^(UL) is an uplinkbandwidth configuration expressed with a multiple of N_(SC) ^(RB).N_(SC) ^(RB) is a size of a resource block in a frequency domain and isexpressed with the number of subcarriers. When the PRB is mapped to aPRB, the PUCCH can be mapped in the order of an outer PRB and an innerPRB. In addition, it can be mapped in the order of a PUCCH format2/2a/2b, an ACK/NACK combination format, and a PUCCH format 1/1a/1b.

In the PUCCH format 1/1a/1b, m can be determined by Equation 3.

$\begin{matrix}{m = \left\{ {{\begin{matrix}N_{RB}^{(2)} & {{{if}\mspace{14mu} n_{PUCCH}^{(1)}} < {c \cdot {N_{cs}^{(1)}/\Delta_{shift}^{PUCCH}}}} \\{\left\lfloor \frac{n_{PUCCH}^{(1)} - {c \cdot {N_{cs}^{(1)}/\Delta_{shift}^{PUCCH}}}}{c \cdot {N_{sc}^{RB}/\Delta_{shift}^{PUCCH}}} \right\rfloor + N_{RB}^{(2)} + \left\lceil \frac{N_{cs}^{(1)}}{8} \right\rceil} & {otherwise}\end{matrix}c} = \left\{ \begin{matrix}3 & {{normal}\mspace{14mu} {cyclic}\mspace{14mu} {prefix}} \\2 & {{extended}\mspace{14mu} {cyclic}\mspace{14mu} {prefix}}\end{matrix} \right.} \right.} & {< {{Equation}\mspace{14mu} 3} >}\end{matrix}$

In Equation 3, N_(RB) ⁽²⁾ denotes a bandwidth expressed with a resourceblock that can be used in the PUCCH format 2/2a/2b in each slot.n_(PUCCH) ⁽¹⁾ denotes an index of a resource used for PUCCH format1/1a/1b transmission. N_(CS) ⁽¹⁾ denotes the number of cyclic shiftvalues used for the PUCCH format 1/1a/1b in a resource block used in amixed structure of the PUCCH format 1/1a/1b and format 2/2a/2b.

In the PUCCH format 2/2a/2b, m can be determined by Equation 4.

m=└n _(PUCCH) ⁽²⁾ /N _(sc) ^(RB)┘  <Equation 4>

In an LTE-A system, UL adopts an SC-FDMA transmission scheme. Atransmission scheme in which IFFT is performed after DFT spreading iscalled SC-FDMA. SC-FDMA may also be called a discrete Fourier transformspread (DFT-s) OFDM. In SC-FDMA, the peak-to-average power ratio (PAPR)or a cubic metric (CM) may be lowered. If the SC-FDMA transmissionscheme is used, transmission power efficiency in a UE having limitedpower consumption may be increased because the non-linear distortionperiod of a power amplifier may be avoided. Consequently, userthroughput may be increased.

FIG. 9 shows an example of the structure of a transmitter in an SC-FDMAsystem.

Referring to FIG. 9, the transmitter 50 includes a discrete Fouriertransform (DFT) unit 51, a subcarrier mapper 52, an inverse fast Fouriertransform (IFFT) unit 53, and a cyclic prefix (CP) insertion unit 54.The transmitter 50 may include a scramble unit (not shown), a modulationmapper (not shown), a layer mapper (not shown), and a layer permutator(not shown), which may be placed in front of the DFT unit 51.

The DFT unit 51 outputs complex-valued symbols by performing DFT oninput symbols. For example, when Ntx symbols are input (where Ntx is anatural number), a DFT size is Ntx. The DFT unit 51 may be called atransform precoder. The subcarrier mapper 52 maps the complex-valuedsymbols to the respective subcarriers of the frequency domain. Thecomplex-valued symbols may be mapped to resource elements correspondingto a resource block allocated for data transmission. The subcarriermapper 52 may be called a resource element mapper. The IFFT unit 53outputs a baseband signal for data (that is, a time domain signal) byperforming IFFT on the input symbols. The CP insertion unit 54 copiessome of the rear part of the baseband signal for data and inserts thecopied parts into the former part of the baseband signal for data.Orthogonality may be maintained even in a multi-path channel becauseinter-symbol interference (ISI) and inter-carrier interference (ICI) areprevented through CP insertion.

FIG. 10 shows an example of a scheme in which the subcarrier mapper mapsthe complex-valued symbols to the respective subcarriers of thefrequency domain.

Referring to FIG. 10( a), the subcarrier mapper maps the complex-valuedsymbols, outputted from the DFT unit, to subcarriers contiguous to eachother in the frequency domain. ‘0’ is inserted into subcarriers to whichthe complex-valued symbols are not mapped. This is called localizedmapping. In a 3GPP LTE system, a localized mapping scheme is used.Referring to FIG. 10( b), the subcarrier mapper inserts an (L−1) numberof ‘0’ every two contiguous complex-valued symbols which are outputtedfrom the DFT unit (L is a natural number). That is, the complex-valuedsymbols outputted from the DFT unit are mapped to subcarriersdistributed at equal intervals in the frequency domain. This is calleddistributed mapping. If the subcarrier mapper uses the localized mappingscheme as in FIG. 10( a) or the distributed mapping scheme as in FIG.10( b), a single carrier characteristic is maintained.

A clustered DFT-s OFDM transmission scheme is a modification of theexisting SC-FDMA transmission scheme and is a method of dividing datasymbols, subjected to a precoder, into a plurality of subblocks,separating the subblocks, and mapping the subblocks in the frequencydomain.

FIG. 11 shows an example of a transmitter using the clustered DFT-s OFDMtransmission scheme.

Referring to FIG. 11, the transmitter 70 includes a DFT unit 71, asubcarrier mapper 72, an IFFT unit 73, and a CP insertion unit 74. Thetransmitter 70 may further include a scramble unit (not shown), amodulation mapper (not shown), a layer mapper (not shown), and a layerpermutator (not shown), which may be placed in front of the DFT unit 71.

Complex-valued symbols outputted from the DFT unit 71 are divided into Nsubblocks (N is a natural number). The N subblocks may be represented bya subblock #1, a subblock #2, . . . , a subblock #N. The subcarriermapper 72 distributes the N subblocks in the frequency domain and mapsthe N subblocks to subcarriers. The NULL may be inserted every twocontiguous subblocks. The complex-valued symbols within one subblock maybe mapped to subcarriers contiguous to each other in the frequencydomain. That is, the localized mapping scheme may be used within onesubblock.

The transmitter 70 of FIG. 11 may be used both in a single carriertransmitter or a multi-carrier transmitter. If the transmitter 70 isused in the single carrier transmitter, all the N subblocks correspondto one carrier. If the transmitter 70 is used in the multi-carriertransmitter, each of the N subblocks may correspond to one carrier.Alternatively, even if the transmitter 70 is used in the multi-carriertransmitter, a plurality of subblocks of the N subblocks may correspondto one carrier. Meanwhile, in the transmitter 70 of FIG. 10, a timedomain signal is generated through one IFFT unit 73. Accordingly, inorder for the transmitter 70 of FIG. 10 to be used in a multi-carriertransmitter, subcarrier intervals between contiguous carriers in acontiguous carrier allocation situation must be aligned.

FIG. 12 shows another example of a transmitter using the clustered DFT-sOFDM transmission scheme.

Referring to FIG. 12, the transmitter 80 includes a DFT unit 81, asubcarrier mapper 82, a plurality of IFFT units 83-1, 83-2, . . . , 83-N(N is a natural number), and a CP insertion unit 84. The transmitter 80may further include a scramble unit (not shown), a modulation mapper(not shown), a layer mapper (not shown), and a layer permutator (notshown), which may be placed in front of the DFT unit 71.

IFFT is individually performed on each of N subblocks. An nth IFFT unit83-n outputs an nth baseband signal (n=1, 2, . . . , N) by performingIFFT on a subblock #n. The nth baseband signal is multiplied by an nthcarrier signal to produce an nth radio signal. After the N radio signalsgenerated from the N subblocks are added, a CP is inserted by the CPinsertion unit 84. The transmitter 80 of FIG. 12 may be used in adiscontinuous carrier allocation situation where carriers allocated tothe transmitter are not contiguous to each other.

FIG. 13 is another example of a transmitter using the clustered DFT-sOFDM transmission scheme.

FIG. 13 is a chunk-specific DFT-s OFDM system performing DFT precodingon a chunk basis. This may be called Nx SC-FDMA. Referring to FIG. 13,the transmitter 90 includes a code block division unit 91, a chunkdivision unit 92, a plurality of channel coding units 93-1, . . . ,93-N, a plurality of modulators 94-1, . . . , 94-N, a plurality of DFTunits 95-1, . . . , 95-N, a plurality of subcarrier mappers 96-1, . . ., 96-N, a plurality of IFFT units 97-1, . . . , 97-N, and a CP insertionunit 98. Here, N may be the number of multiple carriers used by amulti-carrier transmitter. Each of the channel coding units 93-1, . . ., 93-N may include a scramble unit (not shown). The modulators 94-1, . .. , 94-N may also be called modulation mappers. The transmitter 90 mayfurther include a layer mapper (not shown) and a layer permutator (notshown) which may be placed in front of the DFT units 95-1, . . . , 95-N.

The code block division unit 91 divides a transmission block into aplurality of code blocks. The chunk division unit 92 divides the codeblocks into a plurality of chunks. Here, the code block may be datatransmitted by a multi-carrier transmitter, and the chunk may be a datapiece transmitted through one of multiple carriers. The transmitter 90performs DFT on a chunk basis. The transmitter 90 may be used in adiscontinuous carrier allocation situation or a contiguous carrierallocation situation.

Meanwhile, a 3GPP LTE-A system supports a carrier aggregation system.3GPP TR 36.815 V9.0.0 (2010-3) may be incorporated herein by referenceto describe the carrier aggregation system.

The carrier aggregation system implies a system that configures awideband by aggregating one or more carriers having a bandwidth smallerthan that of a target wideband when the wireless communication systemintends to support the wideband. The carrier aggregation system can alsobe referred to as other terms such as a multiple carrier system, abandwidth aggregation system, or the like. The carrier aggregationsystem can be divided into a contiguous carrier aggregation system inwhich carriers are contiguous to each other and a non-contiguous carrieraggregation system in which carriers are separated from each other. Inthe contiguous carrier aggregation system, a guard band may existbetween carriers. A carrier which is a target when aggregating one ormore carriers can directly use a bandwidth that is used in the legacysystem in order to provide backward compatibility with the legacysystem. For example, a 3GPP LTE system can support a bandwidth of 1.4MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz, and a 3GPP LTE-A systemcan configure a wideband of 20 MHz or higher by using only the bandwidthof the 3GPP LTE system. Alternatively, the wideband can be configured bydefining a new bandwidth without having to directly use the bandwidth ofthe legacy system.

In the carrier aggregation system, a UE can transmit or receive one or aplurality of carriers simultaneously according to capacity. An LTE-A UEcan transmit or receive a plurality of carriers simultaneously. An LTERel-8 UE can transmit or receive only one carrier when each of carriersconstituting the carrier aggregation system is compatible with an LTERel-8 system. Therefore, when the number of carriers used in the uplinkis equal to the number of carriers used in the downlink, it is necessaryto configure such that all CCs are compatible with the LTE Rel-8 system.

In order to efficiently use the plurality of carriers, the plurality ofcarriers can be managed in a media access control (MAC). Totransmit/receive the plurality of carriers, a transmitter and a receiverboth have to be able to transmit/receive the plurality of carriers.

FIG. 14 shows an example of a transmitter and a receiver whichconstitute a carrier aggregation system.

In the transmitter of FIG. 14( a), one MAC transmits and receives databy managing and operating all of n carriers. This is also applied to thereceiver of FIG. 14( b). From the perspective of the receiver, onetransport block and one HARQ entity may exist per CC. A UE can bescheduled simultaneously for a plurality of CCs. The carrier aggregationsystem of FIG. 14 can apply both to a contiguous carrier aggregationsystem and a non-contiguous carrier aggregation system. The respectivecarriers managed by one MAC do not have to be contiguous to each other,which results in flexibility in terms of resource management.

FIG. 15 and FIG. 16 are other examples of a transmitter and a receiverwhich constitute a carrier aggregation system.

In the transmitter of FIG. 15( a) and the receiver of FIG. 15( b), oneMAC manages only one carrier. That is, the MAC and the carrier are 1:1mapped. In the transmitter of FIG. 16( a) and the receiver of FIG. 16(b), a MAC and a carrier are 1:1 mapped for some carriers, and regardingthe remaining carriers, one MAC controls a plurality of CCs. That is,various combinations are possible based on a mapping relation betweenthe MAC and the carrier.

The carrier aggregation system of FIG. 14 to FIG. 16 includes ncarriers. The respective carriers may be contiguous to each other or maybe separated from each other. The carrier aggregation system can applyboth to uplink and downlink transmissions. In a TDD system, each carrieris configured to be able to perform uplink transmission and downlinktransmission. In an FDD system, a plurality of CCs can be used bydividing them for an uplink usage and a downlink usage. In a typical TDDsystem, the number of CCs used in uplink transmission is equal to thatused in downlink transmission, and each carrier has the same bandwidth.The FDD system can configure an asymmetric carrier aggregation system byallowing the number of carriers and the bandwidth to be differentbetween uplink and downlink transmissions.

Meanwhile, from a perspective of a UE, there is one transport block andone hybrid automatic repeat request (HARQ) entity per scheduledcomponent carrier. Each transport block is mapped to only a singlecomponent carrier. The UE can be simultaneously mapped to multiplecomponent carriers.

In what follows, a method for encoding uplink control informationaccording to the present invention will be described.

FIG. 17 illustrates three entities. Feedback information on the threeentities can be transmitted through an arbitrary channel for downlink oruplink. If it is assumed that five states are allowed for each entity,the number of bits required for feedback of the five states would belog₂ 5=2.2319<3. Therefore, three bits are allocated for feedback ofeach entity, and a total of nine bits are allocated to transmit feedbackinformation of the three entities. However, the three entities can takea total of 15 states and the number of bits required for feedback of the15 states becomes log₂ 15=3.9069<4. Accordingly, five bits are remainedunused.

Therefore, to transmit feedback information of a plurality of entitiesefficiently, the present invention provides a method for transmittingfeedback information by encoding the feedback information into a binarybit stream so that channel coding or modulation may be carried out withan optimized bit size for the corresponding state information. Also, thepresent invention provides a method for decoding a binary bit streamencoded at a receiver back to the corresponding state information. Thepresent invention encodes feedback information as a closed-form, therebyobviating an encoding table. Therefore, the present invention does notrequire a memory to store an encoding table. However, the presentinvention still allows implementation for generating an encoding tableand storing the table into a memory for later use. Meanwhile, in thefollowing, an entity may represent a codeword, a downlink componentcarrier (DL CC), an uplink component carrier (UL CC), a base station, aterminal, a relay station, or a pico/femto cell. Also, in what follows,feedback information may correspond to one of control signals, includinga HARQ ACK/NACK signal, DTX (discontinuous transmission), a channelquality indicator (CQI), a precoding matrix indicator (PMI), a rankindicator (RI), and covariance matrix.

FIG. 18 illustrates a plurality of entities. A total of N entities existand it is assumed that the number of state information for the entity #i(i.e., the amount of feedback information) is M(i). Therefore, the totalamount of feedback becomes N*M(i).

FIG. 19 is an example of a method for transmitting feedback informationaccording to an embodiment of the present invention.

With reference to FIG. 19, state information for feedback of each entityis combined together and encoded into a binary stream at step S100.Encoding into the binary stream may be carried out by a state-to-bitencoder, which will be described later in FIG. 20.

Channel coding for the binary stream is carried out at step S101. For achannel coding scheme, one of various types of coding methods, includingrepetition, simplex coding, RM coding, punctured RM coding, tail-bitingconvolutional coding (TBCC), low density parity check (LDPC) coding, andturbo coding, can be employed. Rate-matching may be applied to theencoding information bit generated as a result of channel coding bytaking account of a modulation symbol order to be applied and resourcesto be mapped. Cell-specific scrambling using a scrambling codecorresponding to a cell ID or UE-specific scrambling using a scramblingcode corresponding to a UE ID (e.g., radio network temporary identifier(RNTI)) may be applied for randomization of inter-cell interference(ICI) for generated encoding information bit.

The encoding information bit is modulated by a modulator at step S102.For a modulation scheme, various types of modulation methods can beused, including binary phase shift keying (BPSK), quadrature phase shiftkeying (QPSK), 16 QAM (quadrature amplitude modulation), and 64 QAM.Complex modulated symbols are generated as the encoding information bitis modulated.

FIG. 20 is an example of a method for encoding uplink controlinformation carried out by a state-bit encoder according to anembodiment of the present invention.

The state-bit encoder obtains state information S(i) for each entity atstep S110.

The state-bit encoder combines the state information S(i) and generatessynthesized state information at step S111. The state-bit encoderencodes the synthesized state information into a binary stream at stepS112.

In what follows, a method for encoding uplink control informationaccording to the present invention will be described in more detail.

Suppose state information for an entity i is S(i). Then, synthesizedstate information S_(total) can be generated according to Equation 5. Ifit is assumed that the number of entities is N, i=0, . . . , N−1, and ifthe number of states of the entity i, namely, the amount of feedback ofthe entity i is M(i), 0≦S(i)<M(i).

S _(total) =S(0)+K ₀ ·M(0)

where

K _(n) =S(n+1)+K _(n+1) ·M(n+1)

n=0, . . . ,N−1

K _(N-1)=0  <Equation 5>

At this time, S_(total) may be a decimal number. Equation 5 is oneexample of mathematical equations that generate S_(total) as i isincreased from its smallest value. However, S_(total) can be generatedregardless of the order of magnitude of i. In the subsequentdescription, it is assumed that S_(total) is generated according toEquation 5.

If the number of states of each entity is the same to each other,namely, if the amount of feedback of each entity is the same to eachother, M=M(n), n=0, . . . , N−1 and Equation 5 can be expressed byEquation 6.

S _(total) =S(0)+ . . . +S(N−1)·M ^(N-1)  <Equation 6>

In other words, each digit of a number, which is an M-nary expression ofS_(total) according to Equation 6, now represents the state informationfor each entity.

If S_(total) generated according to Equation 5 is converted into abinary stream, the binary stream can be expressed as [b₀ b₁ . . .b_(L-1)] and each individual binary value b_(n) can be obtained byEquation 7.

S _(total) =b ₀ + . . . +b _(L-1)·2^(L-1)

S _(total) =b _(L-1) +b _(L-2)·2¹ . . . +b ₀·2^(L-1)  <Equation 7>

At this time, L can be expressed as

$L = {\left\lceil {\log_{2}\left( {\prod\limits_{i = 0}^{N - 1}\; {M(i)}} \right)} \right\rceil.}$

If conversion into a binary stream as expressed in Equation 7 is basedon Equation 6, L can be expressed as L=┌log₂(M^(N))┐.

Meanwhile, the order of binary values within a binary stream generatedaccording to Equation 7 can be changed. In other words, interleaving canbe applied to the binary stream. Interleaving is introduced to reinforcethe randomization effect. For example, if a binary stream generated whenL=4 is [b0 b1 b2 b3], [b2 b0 b3 b1] can be generated by applying one ofrandomized interleaving patterns. The interleaving pattern can beapplied in such a way of changing the order of b_(n) appearing in thefirst equation of Equation 7 in a random manner. Also, the interleavingpattern can be applied being optimized by taking the hamming distanceinto account. An interleaver carrying out interleaving may be a randominterleaver or a pre-determined interleaver or a random interleavergenerated by incorporating a physical cell ID (PCI) generated by a PNcode or UE-ID (e.g., cell-radio network temporary identifier (C-RNTI))as a seed. Interleaving may also be applied to encoding information bitgenerated by channel coding. In the following description, it is assumedthat a binary stream is generated by the first equation of Equation 7without taking account of interleaving.

FIG. 21 is an example of a method for receiving feedback informationwhen the corresponding feedback information is transmitted by a methodfor encoding uplink control information according to an embodiment ofthe present invention.

A filtered complex symbol is demodulated at step S200. A modulationscheme employed for modulating complex modulation symbols may be usedfor a demodulation scheme. In other words, various types of demodulationschemes can be used, including BPSK, QPSK, 16 QAM, and 64 QAM. While thefiltered complex symbols are demodulated, a log-likelihood ratio (LLR)values are calculated.

Channel decoding is carried out for the LLR value at step S201. Achannel coding scheme employed for channel coding can also be used as achannel decoding scheme. In other words, for a channel decoding method,one of various kinds of decoding schemes including simple repetition,simplex coding, RM coding, punctured RM coding, TBCC, LDPC coding, andturbo coding may be used. By channel decoding, a binary streamincorporating state information is reconstructed.

The binary stream is decoded into state information for each entity atstep S202. Decoding to the state information for each entity may becarried out by a state-to-bit decoder, which will be described later inFIG. 22.

FIG. 22 is an example of a method for decoding uplink controlinformation carried out by a state-bit decoder according to anembodiment of the present invention.

A state-to-bit decoder obtains a binary stream for which channeldecoding has been carried out at step S210.

The state-to-bit decoder decodes the binary stream obtained intosynthesized state information at step S211.

The state-to-bit decoder obtains state information for each entity fromthe synthesized state information at step S212.

Now, a method for decoding uplink control information according to thepresent invention is described in more detail. A method for decodinguplink control information is carried out in a reverse order of a methodfor uplink control information encoding method.

If it is assumed that a bit steam obtained by demodulating a receivedsignal and carrying out channel decoding is [b₀′ b₁′ . . . b_(L-1)],synthesized state information S_(total)′ which can be obtained from thebit stream can be calculated by Equation 8.

S _(total) ′=b ₀ ′+ . . . +b _(L-1)′·2^(L-1)  <Equation 8>

State information S(i)′ for each entity can be calculated by Equation 9.

S _(total) =S′(0)+K ₀ ′·M(0)

where

K _(n) ′=S′(n+1)+K _(n+1) ′·M(n+1)

n=0, . . . ,N−1

K _(N-1)′=0  <Equation 9>

If the amount of feedback of each entity is the same to each other,namely, if M=M(n), n=0, 1, . . . , N−1, state information S(i)′ for eachentity can be calculated by Equation 10.

S _(total) ′=S′(0)+ . . . +S′(N−1)·M ^(N-1)  <Equation 10>

In what follows, a method for encoding uplink control informationaccording to the present invention will be described with reference to aspecific embodiment.

First, described will be an example of a method for encoding uplinkcontrol information in the case where each DL CC transmits two codewordsin a carrier aggregation system comprised of five DL CCs.

FIG. 23 is a block diagram illustrating a case where one UL CCcorresponds to five DL CCs in a carrier aggregation system. For theconvenience of description, the present invention assumes an asymmetriccarrier aggregation system comprised of five DL CCs and one UL CC.However, the present invention is not limited to the above assumption.Therefore, the present invention can be applied to various kinds ofDL-UL configurations. With reference to FIG. 23, downlink data aretransmitted on each PDSCH of DL CC #0 to #4 and feedback informationsuch as ACK/NACK signal or DTX signal in response to the data can betransmitted through PUCCH, extended PUCCH, or PUSCH of UL CC #0.

If the present invention is applied to the carrier aggregation system ofFIG. 23, each DL CC may correspond to one entity and feedbackinformation becomes ACK/NACK signal or DTX signal. Also, it is assumedthat two bits of ACK/NACK state and DTX state about two codewords aresupported. In other words, since five pieces of state information areneeded for each DL CC, a total of 3125 (=5⁵) pieces of state informationare needed.

A state index can be mapped to each of five pieces of state informationfor one DL CC. Tables 13 to 16 are one example of mapping state index tostate information. At this time, mapping of state index and ACK/NACK/DTXstate may take account of hamming distance. Also, it should be notedthat Tables 13 to 16 are just an example, and state index and stateinformation can be mapped in various ways. Also, mapping of state indexand state information can be carried out in the same way for all of CCs.

TABLE 13 State index Information (codeword0/codeword1) 0 ACK/ACK 1NACK/ACK 2 NACK/NACK 3 ACK/NACK 4 DTX

TABLE 14 State index Information (codeword0/codeword1) 0 DTX 1 ACK/ACK 2NACK/ACK 3 NACK/NACK 4 ACK/NACK

TABLE 15 State index Information (codeword0/codeword1) 0 ACK/ACK 1NACK/ACK 2 DTX 3 ACK/NACK 4 NACK/NACK

TABLE 16 State index Information (codeword0/codeword1) 0 DTX 1 ACK/NACK2 NACK/NACK 3 NACK/ACK 4 ACK/ACK

Also, state index and state information can be mapped differently foreach CC. As mapping is applied differently for each CC, randomizationcan be further facilitated for generation of synthesized stateinformation by combining state information among CCs. Tables 17 and 18are one example where state index and state information are mappeddifferently for each CC. Table 17 corresponds to the case where mappingof state index and state information is carried out by circular shiftfor each DL CC. Table 18 corresponds to the case where mapping of stateindex and state information is mirrored. For example, state informationmapped respectively to state indices 0 to 4 at DL CC #0 is mapped tostate indices 4 to 0 for DL CC #1.

TABLE 17 Information for CC #0 Information for CC #1 State index(codeword0/codeword1) (codeword0/codeword1) 0 ACK/ACK DTX 1 NACK/ACKACK/ACK 2 NACK/NACK NACK/ACK 3 ACK/NACK NACK/NACK 4 DTX ACK/NACK

TABLE 18 Information for CC #0 Information for CC #1 State index(codeword0/codeword1) (codeword0/codeword1) 0 ACK/ACK DTX 1 NACK/ACKACK/NACK 2 NACK/NACK NACK/NACK 3 ACK/NACK NACK/ACK 4 DTX ACK/ACK

At this time, when a UE detects a DTX state, the concept of a downlinkassignment index (DAI) used in the LTE rel-8 can be applied. In the LTErel-8, DAI can specify the accumulated number of PDSCHs assigned andPDCCHs mapped. The DAI may be transmitted through a PDCCH. In otherwords, to detect the DTX state, a UE can count DL CCs which are actuallybeing transmitted by employing the concept of DAI. For example, if abase station transmits downlink data through PDSCHs of DL CC #0, DL CC#1, and DL CC #2, 0, 1, and 2 may be assigned to the respective DAIvalues within PDCCHs for PDSCH transmission of DL CC #0, DL CC #1, andDL CC #2. Since it can be known through the DAI whether a UE has failedin decoding PDCCH of DL CC #2, occurrence of the DTX state in thecorresponding DL CC can be detected. The total number of DL CCstransmitted can be known through the DAI. At this time, the DAI valuemay be set to 3 for each DL CC.

Now, it is assumed that state index and state information are mappedaccording to Table 13. If it is assumed that downlink data aretransmitted through PDSCH for all of five DL CCs, UL CC #0 must transmitstate information for the five DL CCs. It is assumed that a UE providesfeedback for each DL CC as follows. The UE provides ACK/NACK as stateinformation for DL CC #0. Accordingly, state index is 3 and S(0)=3. TheUE provides ACK/ACK as state information for DL CC #1. Therefore, stateindex is 0 and S(1)=0. The UE provides DTX as state information for DLCC #2. Then, state index is 4 and S(2)=4. The UE provides NACK/NACK asstate information for DL CC #3. Accordingly, state index is 2 andS(3)=2. And the UE provides NACK/ACK as state information for DL CC #4.Therefore, state index is 1 and S(4)=1. In the present embodiment, sinceM=M(n), n=0, . . . , N−1, according to Equation 6, synthesized stateinformation can be calculated as shown in Equation 11.

$\begin{matrix}\begin{matrix}{S_{total} = {{S(0)} + {{S(1)} \cdot M^{1}} + {{S(2)} \cdot M^{2}} + {{S(3)} \cdot M^{3}} +}} \\{{{S(4)} \cdot M^{4}}} \\{= {3 + {0 \cdot 5^{1}} + {4 \cdot 5^{2}} + {2 \cdot 5^{3}} + {1 \cdot 5^{4}}}} \\{= 978}\end{matrix} & {< {{Equation}\mspace{14mu} 11} >}\end{matrix}$

Meanwhile, the length of a binary stream is L=┌log₂(5⁵)┐=12. Equation 12shows a binary stream [b₀ . . . b₁₁] calculated by using the firstequation of Equation 7.

[b ₀ . . . b ₁₁]=[0 1 0 0 1 0 1 1 1 1 0 0]  <Equation 12>

A UE performs channel coding for the binary stream and carries outmodulation by applying a modulation scheme such as QPSK and transmitsthe modulated binary stream to a base station. The base station receivesand demodulates the binary stream, and performs channel coding by usingan LLR value. If it is assumed that no error bit is found after thechannel decoding, the received bit can be expressed as shown in Equation13. Since the binary stream has no error bits, Equation 13 gives thesame binary stream as expressed by Eq. 12.

[b ₀ ′ . . . b ₁₁′]=[0 1 0 0 1 0 1 1 1 1 0 0]  <Equation 13>

If a transmitter, namely, a UE has performed interleaving,de-interleaving may be carried out. If the transmitter has performedinterleaving after channel coding, a receiver may performde-interleaving before channel decoding.

If a received binary stream of Equation 13 is decoded into synthesizedstate information by Equation 8, the decoding result may be expressed byEquation 14 as follows.

$\begin{matrix}\begin{matrix}{S_{total}^{\prime} = {b_{0}^{\prime} + \ldots + {b_{L - 1}^{\prime} \cdot 2^{L - 1}}}} \\{= {0 + {1 \cdot 2^{1}} + {0 \cdot 2^{2}} + {0 \cdot 2^{3}} + {1 \cdot 2^{4}} + {0 \cdot 2^{5}} +}} \\{{{1 \cdot 2^{6}} + {1 \cdot 2^{7}} + {1 \cdot 2^{8}} + {1 \cdot 2^{9}} + {0 \cdot 2^{10}} + {0 \cdot 2^{11}}}} \\{= 978}\end{matrix} & {< {{Equation}\mspace{14mu} 14} >}\end{matrix}$

If the synthesized state information S_(total)′ of Equation 14 is soughtby using Equation 10, state information for each DL CC can be detected.In other words, since state information for DL CC #0 is S′(0)=3,ACK/NACK state is detected. Since state information for DL CC #1 isS′(1)=0, ACK/ACK state is detected. Since state information for DL CC #2is S′(2)=4, DTX state is detected. Since state information for DL CC #3is S′(3)=2, NACK/NACK state is detected. Since state information for DLCC #4 is S′(4)=−1, NACK/ACK state is detected.

In what follows, described will be an example of a method for encodinguplink control information for the case where each DL CC transmits oneor two codewords in a carrier aggregation system comprised of five DLCCs.

In providing state information for a DL CC through which one codeword istransmitted, state index and state information can be mapped as shown inTable 19. The number of state information required when a codewordtransmitted is 1 reduces from 5 to 3. Mapping between state index andstate information is not limited to the mapping relationship shown inTable 19.

TABLE 19 State index Information (codeword0 only) 0 ACK 1 NAK 2 DTX

In the present embodiment, it is assumed that mapping between stateindex and state information for a DL CC through which two codewords aretransmitted is performed according to Table 13 while mapping betweenstate index and state information for a DL CC through which one codewordis transmitted is performed according to Table 19. In other words, thenumber of state information varies according to the number of codewordstransmitted through each DL CC. The above situation may be regarded thatstate reduction is applied. For example, if DL CC #0 and DL CC #1transmit two codewords and one codeword, respectively, the number ofstate information for DL CC #0 is 5 and the number of state informationfor DL CC #1 is 3. Therefore, a total of 15 pieces of state information(namely, 4 bits) can be generated. The number of codewords transmittedthrough DL CC can be determined by a rank determined according to atransmission mode. Table 20 illustrates one example of a transmissionmode defined by the LTE rel-9.

TABLE 20 transmission mode Notes 1 Transmission from a single eNBantenna port 2 Transmit diversity 3 Open-loop spatial multiplexing 4Closed-loop spatial multiplexing 5 Multi-user MIMO 6 Closed-loop rank-1precoding 7 transmission using UE-specific reference signal 8 Dual-layerbeamforming

With reference to Table 20, two codewords can be transmitted when thetransmission mode is 3, 4, 5, or 8, and the number of ranks is two ormore. For the remaining transmission modes, only one codeword can betransmitted. At this time, the rank may or may not be the same as thenumber of layers.

If it is assumed that downlink data are transmitted through PDSCH forall of the five DL CCs, UL CC #0 must transmit all the state informationfor bout the five DL CCs. It is assumed that DL CC #0, #2, and #3transmit two codewords while DL CC #1 and #4 transmit one codeword. A UEis assumed to provide feedback for each DL CC as follows. The terminalprovides NACK/NACK as state information for DL CC #0. Accordingly, stateindex is 2 and S(0)=2 and M(0)=5. The UE provides NACK as stateinformation for DL CC #1. Accordingly, state index is 1 and S(1)=1 andM(1)=3. The UE provides DTX as state information for DL CC #2.Accordingly, state index is 4 and S(2)=4 and M(2)=5. The UE providesACK/NACK as state information for DL CC #3. Accordingly, state index is3 and S(3)=3 and M(3)=5. And the UE provides DTX as state informationfor DL CC #4. Accordingly, state index is 2 and S(4)=2 and M(4)=3.

Synthesized state information S_(total) according to Equation 5 can becalculated as shown in Equation 15.

$\begin{matrix}{{K_{4} = 0}{K_{3} = {{{S(4)} + {K_{4} \cdot {M(4)}}} = {{2 + {0 \cdot 3}} = 2}}}{K_{2} = {{{S(3)} + {K_{3} \cdot {M(3)}}} = {{3 + {2 \cdot 5}} = 13}}}{K_{1} = {{{S(2)} + {K_{2} \cdot {M(2)}}} = {{4 + {13 \cdot 5}} = 69}}}{K_{0} = {{{S(1)} + {K_{1} \cdot {M(1)}}} = {{1 + {69 \cdot 3}} = 207}}}\begin{matrix}{S_{total} = {{S(0)} + {K_{0} \cdot {M(0)}}}} \\{= {2 + {207 \cdot 5}}} \\{= 1037}\end{matrix}} & {< {{Equation}\mspace{14mu} 15} >}\end{matrix}$

Meanwhile, the length of a binary stream is

$L = {\left\lceil {\log_{2}\left( {\prod\limits_{i = 0}^{N - 1}\; {M(i)}} \right)} \right\rceil = {\left\lceil {\log_{2}\left( {5 \cdot 3 \cdot 5 \cdot 5 \cdot 3} \right)} \right\rceil = {\left\lceil {\log_{2}(1125)} \right\rceil = 11}}}$

If the length above is compared with that of a case where all of five DLCCs transmit two codewords, it can be known that the length of thebinary stream has been reduced by 1 bit. Also, since the binary streamundergoes channel coding and eventually encoding information bits of thesame size are generated, an advantageous effect of reducing a code rate(CR) is obtained. Therefore, false alarm rate can be further reduced.

If the binary stream [b₀ . . . b₁₀] is calculated by using the firstequation of Equation 7, the result can be expressed as shown in Equation16.

[b ₀ . . . b ₁₀]=[1 0 1 1 0 0 0 0 0 0 1]  <Equation 16>

A UE applies channel coding to the binary stream and modulates thebinary stream by applying a modulation scheme such as QPSK and transmitsthe binary stream to a base station. The base station receives anddemodulates the binary stream and performs channel decoding by using LLRvalue. If no error bit is found after channel decoding, the receivedbits can be expressed as shown in Equation 17. Since no error bit isfound, Equation 17 provides the same binary stream of Equation 16.

[b ₀ ′ . . . b ₁₀′]=[1 0 1 1 0 0 0 0 0 0 1]  <Equation 17>

If a received binary stream of Equation 17 is decoded into synthesizedstate information according to Equation 8, the result is expressed asshown in Equation 18.

$\begin{matrix}\begin{matrix}{S_{total}^{\prime} = {b_{0}^{\prime} + \ldots + {b_{L - 1}^{\prime} \cdot 2^{L - 1}}}} \\{= {1 + {0 \cdot 2^{1}} + {1 \cdot 2^{2}} + {1 \cdot 2^{3}} + {0 \cdot 2^{4}} + {0 \cdot 2^{5}} +}} \\{{{0 \cdot 2^{6}} + {0 \cdot 2^{7}} + {0 \cdot 2^{8}} + {0 \cdot 2^{9}} + {1 \cdot 2^{10}}}} \\{= 1037}\end{matrix} & {< {{Equation}\mspace{14mu} 18} >}\end{matrix}$

If synthesized state information S_(total)′ of Equation 18 is calculatedaccording to Equation 9, state information for each DL CC can bedetected. In other words, since state information for DL CC #0 isS′(0)=2, NACK/NACK state is detected. Since state information for DL CC#1 is S′(1)=1, NACK state is detected. Since state information for DL CC#2 is S′(2)=4, DTX state is detected. Since state information for DL CC#3 is S′(3)=3, ACK/NACK state is detected. Since state information forDL CC #4 is S′(4)=2, DTX state is detected.

In the case where each DL CC transmits one or two codewords in a carrieraggregation system comprised of 5 DL CCs, state reduction may not beapplied for encoding feedback information. In other words, the number ofstate information for DL CC transmitting one codeword may be 5, which isthe same number of state information for DL CC transmitting twocodewords. Table 21 is one example of mapping state index and stateinformation when DL CC transmits one codeword.

TABLE 21 Information Information Information State (codeword0 only)(codeword0 only) (codeword0 only) index -> Tx side -> Rx side (Method 0)-> Rx side (Method 1) 0 ACK ACK ACK 1 Not Assigned ACK Not Assigned 2NACK NACK NAK 3 Not Assigned NACK Not Assigned 4 DTX DTX DTX

With reference to Table 21, since the Tx side encoding state informationdoes not require five state indices, it maps ACK state, NACK state, andDTX state to state index 0, 2, and 4, respectively, and state index 1and 3 may not be used. The Rx side decoding state information may simplyfollow the mapping relationship at the Tx side (method 1 of Table 21),or state index 1 and 3 may be used for representing ACK and NACK state,respectively. The aforementioned operation of the Rx side implicitlyincreases hamming distance, thereby reducing false alarm rate. Since thepresent embodiment assumes that no error bit has been found aftercarrying out channel decoding, there is no difference between method 0and 1. Mapping between state index and state information for DL CCtransmitting one codeword is not limited to the mapping relationshipshown in Table 21. In the present embodiment, it is assumed that mappingof state index and state information for DL CC transmitting twocodewords follows the mapping relationship of Table 13 while mapping ofstate index and state information for DL CC transmitting one codewordfollows the mapping relationship of Table 21.

If all of the five DL CCs transmit downlink data through PDSCH, UL CC #0must transmit all the state information for the five DL CCs. Now, it isassumed that DL CC #0, #2, and #3 transmit two codewords while DL CC #1and #4 transmit one codeword. A UE is assumed to provide feedback foreach DL CC as follows. The UE provides NACK/NACK as state informationfor DL CC #0. Accordingly, state index is 2 and S(0)=2 and M(0)=5. TheUE provides NACK as state information for DL CC #1. Accordingly, stateindex is 1 and S(1)=1 and M(1)=3. The UE provides DTX as stateinformation for DL CC #2. Accordingly, state index is 4 and S(2)=4 andM(2)=5. The UE provides ACK/NACK as state information for DL CC #3.Accordingly, state index is 3 and S(3)=3 and M(3)=5. And the UE providesDTX as state information for DL CC #4. Accordingly, state index is 2 andS(4)=2 and M(4)=3.

Synthesized state information S_(total) according to Equation 5 can becalculated as shown in Equation 19.

$\begin{matrix}{{K_{4} = 0}{K_{3} = {{{S(4)} + {K_{4} \cdot {M(4)}}} = {{4 + {0 \cdot 5}} = 4}}}{K_{2} = {{{S(3)} + {K_{3} \cdot {M(3)}}} = {{3 + {4 \cdot 5}} = 23}}}{K_{1} = {{{S(2)} + {K_{2} \cdot {M(2)}}} = {{4 + {23 \cdot 5}} = 119}}}{K_{0} = {{{S(1)} + {K_{1} \cdot {M(1)}}} = {{2 + {119 \cdot 5}} = 597}}}\begin{matrix}{S_{total} = {{S(0)} + {K_{0} \cdot {M(0)}}}} \\{= {2 + {597 \cdot 5}}} \\{= 2987}\end{matrix}} & {< {{Equation}\mspace{14mu} 19} >}\end{matrix}$

Meanwhile, the length of a binary stream is

$L = {\left\lceil {\log_{2}\left( {\prod\limits_{i = 0}^{N - 1}\; {M(i)}} \right)} \right\rceil = {\left\lceil {\log_{2}\left( {5 \cdot 5 \cdot 5 \cdot 5 \cdot 5} \right)} \right\rceil = {\left\lceil {\log_{2}(3125)} \right\rceil = 12.}}}$

If the binary stream [b₀ . . . b₁₀] is calculated by using the firstequation of Equation 7, the result can be expressed as shown in Equation20.

[b ₀ . . . b ₁₁]=[1 1 0 1 0 1 0 1 1 1 0 1]  <Equation 20>

A UE applies channel coding to the binary stream and modulates thebinary stream by applying a modulation scheme such as QPSK and transmitsthe binary stream to a base station. The base station receives anddemodulates the binary stream and performs channel decoding by using LLRvalue. If no error bit is found after channel decoding, the receivedbits can be expressed as shown in Equation 21. Since no error bit isfound, Equation 21 provides the same binary stream of Equation 20.

[b ₀ ′ . . . b ₁₁′]=[1 1 0 1 0 1 0 1 1 1 0 1]  <Equation 21>

If a received binary stream of Equation 21 is decoded into synthesizedstate information according to Equation 8, the result is expressed asshown in Equation 22.

$\begin{matrix}\begin{matrix}{S_{total}^{\prime} = {b_{0}^{\prime} + \ldots + {b_{L - 1}^{\prime} \cdot 2^{L - 1}}}} \\{= {1 + {1 \cdot 2^{1}} + {0 \cdot 2^{2}} + {1 \cdot 2^{3}} + {0 \cdot 2^{4}} + {1 \cdot 2^{5}} +}} \\{{{0 \cdot 2^{6}} + {1 \cdot 2^{7}} + {1 \cdot 2^{8}} + {1 \cdot 2^{9}} + {0 \cdot 2^{10}} + {1 \cdot 2^{11}}}} \\{= 2987}\end{matrix} & {< {{Equation}\mspace{14mu} 22} >}\end{matrix}$

If synthesized state information S_(total)′ of Equation 22 is calculatedaccording to Equation 9, state information for each DL CC can bedetected. In other words, since state information for DL CC #0 isS′(0)=2, NACK/NACK state is detected. Since state information for DL CC#1 is S′(1)=1, NACK state is detected. Since state information for f DLCC #2 is S′(2)=4, DTX state is detected. Since state information for DLCC #3 is S′(3)=3, ACK/NACK state is detected. Since state informationfor DL CC #4 is S′(4)=2, DTX state is detected.

In what follows, an extended PUCCH format will be described. TheACK/NACK feedback information described above can be transmitted throughan extended PUCCH format. The extended PUCCH format can substitute forPUCCH format 1/1a/1b or 2/2a/2b of the LTE Rel-8 in a carrieraggregation system for transmission of a lot more payload. As done forthe ACK/NACK feedback information, payload also increases for the casewhere CQI/PMI RI is transmitted for each component carrier. Therefore, anew PUCCH format is required.

FIG. 24 is an example of an extended PUCCH format. The extended PUCCHformat of FIG. 24 may be a PUCCH format to which a DFT-s OFDMtransmission scheme is applied. Although the extended PUCCH format ofFIG. 24 is not limited to a specific PUCCH format, in order tofacilitate explanation, the following description will be based on anormal CP structure of a PUCCH format 1 for carrying ACK/NACK. Theextended PUCCH format is also applicable to PUCCH formats 2/2a/2b forUCI transmission such as CQI/PMI/RI. That is, the extended PUCCH formatis applicable to any control information. For example, it is possible touse the extended PUCCH format proposed to support a 13 (or higher)-bitpayload in the PUCCH format 2 supporting up to a 13-bit payload.

Referring to FIG. 24, channel coding is performed on an information bit(e.g., ACK/NACK, etc.) for each component carrier (step 300). Thechannel coding may be any one of various types of coding schemes, suchas simple repetition, simplex coding, RM coding, punctured RM coding,tail-biting convolutional coding (TBCC), low density parity check (LDPC)coding, or turbo coding. An encoding information bit generated as aresult of channel coding can be rate-matched by considering a modulationsymbol order to be applied and a resource to be mapped. For inter-cellinterface (ICI) randomization for the generated encoding informationbit, cell-specific scrambling using a scrambling code corresponding to acell identifier (ID) or UE-specific scrambling using a scrambling codecorresponding to a UE ID (e.g., a radio network temporary identifier(RNTI)) can be used.

The encoding information bit is distributed to each slot via a divider(step 301). The encoding information bit can be distributed to two slotsin various manners. For example, a first part of the encodinginformation bit can be distributed to a first slot, and a last part ofthe encoding information bit can be distributed to a second slot.Alternatively, by using an interleaving scheme, an even encodinginformation bit can be distributed to the first slot, and an oddencoding information bit can be distributed to the second slot. Theencoding information bit distributed to each slot is modulated via amodulator (step 302). A QPSK symbol can be generated by modulating theencoding information bit. Meanwhile, the modulator and the divider maybe placed in a reverse order.

Discrete Fourier transform (DFT) precoding is performed on QPSK symbolsin each slot to generate a single carrier waveform in each slot (step303). In addition to the DFT precoding, an operation of Walsh precodingor the like corresponding thereto can be performed. However, it isassumed hereinafter that the DFT precoding is performed unless specifiedotherwise.

Time spreading is performed with an SC-FDMA symbol level on QPSK symbolsfor which DFT precoding is performed, by using an orthogonal code havingan index m which is predetermined or determined through dynamicsignaling or radio resource control (RRC) signaling (step 304). Theorthogonal code of the index m can be expressed by w_(m)=[w₀ w₁ w₂ w₃]if a spreading factor (SF) is 4. If the orthogonal code is a Walsh codeand the SF is 4, it can be expressed by w₀=[1 1 1 1], w₁[1 −1 1 −1],w₂=[1 1 −1 −1], w₃=[1 −1 −1 1]. If the orthogonal code is a DFT code, itcan be expressed by w_(m)=[w₀ w₁ . . . w_(k-1)], wherew_(k)=exp(j2πkm/SF). In addition, another code other than the Walsh codeand the DFT code may be used as the orthogonal code. The SF implies afactor by which data is spread, and can be related to the number of UEsto be multiplexed or the number of antennas. The SF may vary dependingon a system, and may be predetermined or may be reported to the UEthrough DCI or RRC signaling. In addition, the orthogonal code appliedwith the SC-FDMA symbol level can be applied by changing an index in aslot level. That is, the orthogonal code can be hopped in the slotlevel.

A signal generated as described above is mapped to a subcarrier in aPRB, is then converted into a signal of a time domain by inverse fastFourier transform (IFFT), and is transmitted via a radio frequency (RF)unit by attaching a cyclic prefix (CP).

FIG. 25 is another example of an extended PUCCH format. Referring toFIG. 25, channel coding is performed on an information bit such asACK/NACK for each component carrier (step 310), and the encodinginformation bit is distributed to each slot via a divider (step 311).The encoding information bit distributed to each slot is modulated via amodulator, and a QPSK symbol generated as a result of modulation istime-spread by an orthogonal code of an index m (step 312). If SF=4, theorthogonal code of the index m can be expressed by w_(m)=[w₀ w₁ w₂ w₃].DFT precoding is performed with an SC-FDMA level on time-spread QPSKsymbols (step 313), and a signal generated in this manner is mapped to asubcarrier in a PRB. That is, the extended PUCCH format of FIG. 25 isdifferent from the extended PUCCH format of FIG. 24in a sense that timespreading is performed before DFT precoding.

FIG. 26 shows an example of time spreading for a modulated QPSK symbolwith an extended PUCCH format. A case where a QPSK symbol is time-spreadin a normal CP is shown in FIG. 26. Referring to FIG. 26, the QPSKsymbol is time-spread across 5 SC-FDMA symbols in one slot. A referencesignal is mapped to 2^(nd) and 6^(th) SC-FDMA symbols in each slot. Thisis the same position to which a reference signal is mapped in PUCCHformats 2/2a/2b in LTE rel-8. When the QPSK symbol is time-spread, anorthogonal code having an index m which is predetermined or determinedthrough dynamic signaling or RRC signaling can be used. If SF=5, theorthogonal code having the index m can be expressed by w_(m)=[w₀ w₁ w₂w₃ w₄]. In addition, the orthogonal code can be hopped in a slot level.

FIG. 27 is another example of time spreading for a modulated QPSK symbolwith an extended PUCCH format. A case where a QPSK symbol is time-spreadin an extended CP is shown in FIG. 27. Referring to FIG. 27, the QPSKsymbol is time-spread across 5 SC-FDMA symbols in one slot. A referencesignal is mapped to a 4^(th) SC-FDMA symbol in each slot. This is thesame position to which a reference signal is mapped in PUCCH formats2/2a/2b in LTE rel-8. When the QPSK symbol is time-spread, an orthogonalcode having an index m which is predetermined or determined throughdynamic signaling or RRC signaling can be used. If SF=5, the orthogonalcode having the index m can be expressed by w_(m)=[w₀ w₁ w₂ w₃ w₄]. Inaddition, the orthogonal code can be hopped in a slot level.

FIG. 28 is another example of an extended PUCCH format. The extendedPUCCH format of FIG. 28 is a case where joint coding is performed on twoslots in a subframe. Referring to FIG. 28, channel coding is performedon an information bit such as ACK/NACK for each component carrier (step320). Since a QPSK modulation scheme is used and mapping is performed ontwo slots through one PRB consisting of 12 subcarriers in the presentembodiment, 48 encoding bits can be generated. The encoding informationbit is modulated via a modulator (step 321). Since a QPSK modulationscheme is used in the present embodiment, 24 QPSK symbols are generated.The QPSK symbols are distributed to each slot via a divider (step 322).The QPSK symbols can be distributed to two slots in various manners. DFTprecoding is performed on the QPSK symbols distributed to each slot viathe divider (step 323). Since 12 QPSK symbols are distributed to eachslot in the present embodiment, 12-point DFT precoding is performed.Time spreading is performed with an SC-FDMA symbol level on QPSK symbolsfor which DFT precoding is performed, by using an orthogonal code havingan index m (step 324). The orthogonal code can be hopped in a slotlevel.

A signal generated as described above is mapped to a subcarrier in aPRB, is then converted into a signal of a time domain by IFFT, and istransmitted via a RF unit by attaching a CP. If SF=4, 12-bit informationfor carrying ACK/NACK for 5 component carriers can be transmitted with acoding rate of 0.0625(=12/48/4), and 4 UEs can be multiplexed per onePRB.

In applying a method for encoding uplink control information accordingto the present invention, the number of bits provided as feedback,namely, the size of a codebook may be determined by various ways.

First, the concept of a cell is described. The concept of a cell can beapplied for the LTE-A system. A cell is an entity comprised of at leastone unit of downlink resources and optionally uplink resources from thepoint of view of a UE. In other words, one cell certainly includes atleast one unit of downlink resources but uplink resources may not benecessarily included. The one unit of downlink resources may correspondto one DL CC. A linkage between carrier frequency of downlink resourcesand that of uplink resources can be specified by SIB2 transmittedthrough downlink resources.

Type of a cell can be classified by an allocation method. First, thenumber of cells allocated for the whole system can be fixed. Forexample, the number of cells allocated for the whole system may be 8.The whole or part of the cells allocated for the entire system may beallocated by a radio resource control (RRC) signaling of an upper layer.A cell allocated by the RRC signaling is called a configured cell. Inother words, a configured cell may indicate the one allocated for use bythe system among cells allocated for the entire system. All or part ofconfigured cells may be allocated by a media access control (MAC)signaling. A cell allocated by the MAC signaling may be called anactivated cell. The remaining cells among configured cells except foractivated cells may be called deactivated cells. The whole or part ofactivated cells is allocated to a UE by an L1/L2 signaling. A cellallocated by the L1/L2 signaling may be called a scheduled cell. Ascheduled cell can receive data through a PDSCH by using downlinkresources within the cell and transmit data through a PUSCH by usinguplink resources within the cell. Since it was assumed in the abovedescription of a method for uplink control information according to thepresent invention that a plurality of DL CCs all transmits data, DL CCsinvolved in this case may all be called scheduled DL CCs.

As described above, when the DAI is transmitted together, the size of acodebook for ACK/NACK feedback can be determined based on the number ofscheduled DL CCs and the number of transmitted codewords determined by atransmission mode and rank within a CC. However, if the size of acodebook is determined based on the number of configured DL CCs insteadof the number of scheduled DL CCs, the DAI does not have to betransmitted. In other words, the size of a codebook can be determinedsemi-statically according to the number of configured DL CCs specifiedby the RRC signaling. Also the size of a codebook can be determineddynamically according to the number of ranks transmitted through atransmission mode and DCI format specified by the RRC signaling. At thistime, the number of ranks transmitted through the DCI format may beexpressed together with precoding vector information. The abovedescription may be consulted in Section 6.3.4.2.3 of 3GPP TS 36.211V8.9.0 (2009-12) “Technical Specification Group Radio Access Network;Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channelsand Modulation (Release 8)”. Table 22 illustrates a codebook of aprecoding matrix when the number of antenna ports is two. With referenceto Table 22, 3 bits are used for precoding information to providefeedback of a total of seven states according to the number of layersand codebook index.

TABLE 22 Number of layers ν Codebook index 1 2 0$\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\1\end{bmatrix}$ $\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 0 \\0 & 1\end{bmatrix}$ 1 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\{- 1}\end{bmatrix}$ $\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 1 \\1 & {- 1}\end{bmatrix}$ 2 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 1 \\j & {- j}\end{bmatrix}$ 3 $\frac{1}{2}\begin{bmatrix}1 \\{- j}\end{bmatrix}$ —

Table 23 illustrates a codebook of a precoding matrix when the number ofantenna ports is four. With reference to Table 23, 6 bits are used forprecoding information to provide feedback of a total of 64 statesaccording to the number of layers and codebook index.

TABLE 23 Codebook Number of layers v index u_(n) 1 2 3 4 0 u₀ = [1 −1 −1−1]^(T) W₀ ^({1}) W₀ ^({14})/{square root over (2)} W₀ ^({124})/{squareroot over (3)} W₀ ^({1234})/2 1 u₁ = [1 −j 1 j]^(T) W₁ ^({1}) W₁^({12})/{square root over (2)} W₁ ^({123})/{square root over (3)} W₁^({1234})/2 2 u₂ = [1 1 −1 1]^(T) W₂ ^({1}) W₂ ^({12})/{square root over(2)} W₂ ^({123})/{square root over (3)} W₂ ^({3214})/2 3 u₃ = [1 j 1−j]^(T) W₃ ^({1}) W₃ ^({12})/{square root over (2)} W₃ ^({123})/{squareroot over (3)} W₃ ^({3214})/2 4 u₄ = [1 (−1 − j)/{square root over (2)}−j (1 − j)/{square root over (2)}]^(T) W₄ ^({1}) W₄ ^({14})/{square rootover (2)} W₄ ^({124})/{square root over (3)} W₄ ^({1234})/2 5 u₅ = [1 (1− j)/{square root over (2)}j (−1 − j)/{square root over (2)}]^(T) W₅^({1}) W₅ ^({14})/{square root over (2)} W₅ ^({124})/{square root over(3)} W₅ ^({1234})/2 6 u₆ = [1 (1 + j)/{square root over (2)}− j (−1 +j)/{square root over (2)}]^(T) W₆ ^({1}) W₆ ^({13})/{square root over(2)} W₆ ^({134})/{square root over (3)} W₆ ^({1324})/2 7 u₇ = [1 (−1 +j)/{square root over (2)}j (1 + j)/{square root over (2)}]^(T) W₇ ^({1})W₇ ^({13})/{square root over (2)} W₇ ^({134})/{square root over (3)} W₇^({1324})/2 8 u₈ = [1 −1 1 1]^(T) W₈ ^({1}) W₈ ^({12})/{square root over(2)} W₈ ^({124})/{square root over (3)} W₈ ^({1234})/2 9 u₉ = [1 −j −1−j]^(T) W₉ ^({1}) W₉ ^({14})/{square root over (2)} W₉ ^({134})/{squareroot over (3)} W₉ ^({1234})/2 10 u₁₀ = [1 1 1 −1]^(T) W₁₀ ^({1}) W₁₀^({13})/{square root over (2)} W₁₀ ^({123})/{square root over (3)} W₁₀^({1324})/2 11 u₁₁ = [1 j −1 j]^(T) W₁₁ ^({1}) W₁₁ ^({13})/{square rootover (2)} W₁₁ ^({134})/{square root over (3)} W₁₁ ^({1324})/2 12 u₁₂ =[1 −1 −1 1]^(T) W₁₂ ^({1}) W₁₂ ^({12})/{square root over (2)} W₁₂^({123})/{square root over (3)} W₁₂ ^({1234})/2 13 u₁₃ = [1 −1 1 −1]^(T)W₁₃ ^({1}) W₁₃ ^({13})/{square root over (2)} W₁₃ ^({123})/{square rootover (3)} W₁₃ ^({1324})/2 14 u₁₄ = [1 1 −1 −1]^(T) W₁₄ ^({1}) W₁₄^({13})/{square root over (2)} W₁₄ ^({123})/{square root over (3)} W₁₄^({3214})/2 15 u₁₅ = [1 1 1 1]^(T) W₁₅ ^({1}) W₁₅ ^({12})/{square rootover (2)} W₁₅ ^({123})/{square root over (3)} W₁₅ ^({1234})/2

Now, a method for determining the size of a codebook according to thenumber of configured DL CCs, a transmission mode, and the number ofranks will be described with reference to an embodiment. For example, itis assumed that the number of antenna ports is 2 and the total number ofconfigured DL CCs is 4. Also, it is further assumed that DTX state isprovided as feedback. If the transmission mode of DL CC #0 is 3 and thenumber of ranks is 2, a total of 5 states can be provided as feedback.If the transmission mode of DL CC #1 is 4 and the number of ranks is 1,a total of 3 states can be provided as feedback. If the transmissionmode of DL CC #2 is 8 and the number of ranks is 2, a total of 5 statescan be provided as feedback.

If the transmission mode of DL CC #3 is 1 and the number of ranks is 1,a total of 3 states can be provided as feedback. Based on the above, thetotal number of states provided as feedback is 225 and the size of acodebook can be expressed by 8 bits (┌log₂(225−1)┐). In the equation forexpressing the codebook, ‘−1’ indicates exclusion of the case where allthe states are of DTX state.

If the DTX state is not provided explicitly but in a state such as NACKstate in the above embodiment, the number of states required for eachconfigured DL CC becomes 4 in the case of transmitting 2 codewords and 2in the case of 1 codeword. In other words, DL CC #0 can provide feedbackof a total of 4 states. DL CC #1 a total of 2 states. DL CC #2 a totalof 4 states. DL CC #3 a total of 2 states. Accordingly, the total numberof feedback states is 64 and the size of the codebook is expressed by 6bits (┌log₂(64−1)┐).

Meanwhile, since a maximum value for the number of ranks isautomatically determined according to a transmission mode, the size of acodebook can be determined based on the number of configured DL CCs andthe number of codewords according to ranks without taking account of atransmission mode specified by the RRC signaling.

Also, the size of a codebook may be determined based only on the numberof DL CCs and a transmission mode. Since the maximum number of codewordsthat can be transmitted in a transmission mode is determined accordingto the corresponding transmission mode, the size of a codebook can bedetermined based on the maximum number of codewords. For example, it isassumed that the total number of DL CCs is 4 and DTX state is providedas feedback. Since a maximum of two codewords can be transmitted whenthe transmission mode of DL CC #0 is 3 and the number of ranks is 2, atotal of five states can be provided as feedback. In the same way, evenif the transmission mode of DL CC #1 is 4 and the number of ranks is 1,a total of five states can be provided as feedback when only thetransmission mode is taken into account. A total of five states can beprovided as feedback when the transmission mode of DL CC #2 is 8 and thenumber of ranks is 2. A total of three states can be provided asfeedback when the transmission mode of DL CC #3 is 1 and the number ofranks is 1. Accordingly, the total number of states provided as feedbackis 375 and the size of a codebook can be expressed by 9 bits(┌log₂(375−1)┐).

If the DTX state is not explicitly provided as feedback in the aboveembodiment, DL CC #0 can provide a total of 4 states as feedback. DL CC#1 a total of 4 states. DL CC #2 a total of 4 states. DL CC #3 a totalof 2 states. Accordingly, the total number of states provided asfeedback is 64 and the size of the codebook becomes 7 bits(┌log₂(128−1)┐).

Also, the size of a codebook may be determined based on the number ofactivated DL CCs or the number of scheduled DL CCs instead of using thenumber of configured DL CCs. In other words, the size of a codebook maybe determined based on the number of activated DL CCs and the number ofcodewords or based on the number of scheduled DL CCs and the number ofcodewords.

Meanwhile, Table 24 is one example of a mapping relationship betweentransport blocks and codewords. With reference to Table 24, if the swapflag value is 0, the transport block 1 is mapped to the codeword 0 whilethe transport block 2 is mapped to the codeword 1. If the swap flagvalue is 1, the transport block 1 is mapped to the codeword 1 while thetransport 2 is mapped to the codeword 0.

TABLE 24 transport block to codeword codeword 0 codeword 1 swap flagvalue (enabled) (enabled) 0 transport block 1 transport block 2 1transport block 2 transport block 1

Meanwhile, even though a transmission mode allows transmission of twocodewords, it is sometimes the case that only one codeword istransmitted irrespective of the transmission mode and the number ofranks. For example, the above case corresponds to the situation whereonly one transport block of the two transport blocks is allowed to betransmitted as shown in Table 25. The above case applied also to thesituation where re-transmission is required only for one codeword ortransmission of one codeword is made possible as a single antennafall-back method is employed. Table 25 is another example of a mappingrelationship between transport blocks and codewords.

TABLE 25 codeword 0 codeword 1 transport block 1 transport block 2(enabled) (disabled) enabled disabled transport block 1 — disabledenabled transport block 2 —

Meanwhile, the size of a codebook may be changed according to the numberof codewords. For convenience of description, it is assumed that thesize of a codebook is determined based on configured DL CCs and NACKstate and DTX state are expressed together. In other words, ACK statecan be mapped to 1 while NACK state and DTX state are mapped to 0.

If it is assumed that four configured DL CCs are employed, according toa transmission mode, the number of codewords transmitted by eachconfigured DL CC becomes 2 for DL CC #0, #1, and #3 while it is 1 forDLCC #2. Also, DL CC #0, #1, and #2 are assumed to be activated DL CCs.At this time, a UE transmits ACK/NACK state only for DL CC which hassuccessfully detected PDCCH and transmits a pre-assigned value when theUE failed to decode PDCCH. At this time, the pre-assigned value maycorrespond to 0. A codebook may comprised of [a0 a1 b0 b1 c0 d0 d1] or[a0 a1 b0 b1 c0 c1 d0 d1]. a0 and a1 are ACK/NACK bit corresponding toeach of a first and a second codeword of DL CC #0. In the same way, b0and b1 correspond to ACK/NACK bit corresponding to a first and a secondcodeword of DL CC #1; c0 and c1, DL CC #2; and d0 and 1, DL CC #3. Inother words, position of ACK/NACK bit for each DL CC can bepre-determined. A codebook of [a0 a1 b0 b1 c0 d0 d1] indicates that thesize of the codebook has been determined based on the number ofcodewords transmitted by each DL CC while a codebook of [a0 a1 b0 b1 c0d0 d1] indicates determination of the size of the codebook based on themaximum number of codewords which can be transmitted by each DL CC.

For example, it is assumed that activated DL CCs, DL CC #0, #1, and #2transmit downlink control signals through a PDCCH and only PDCCHs of DLCC #0 and #2 have been decoded. Also, it is further assumed that all thecodewords corresponding to the above setting have been successfullydecoded. If a codebook is [a0 a1 b0 b2 c0 c1 d0 d1], a UE may provide [11 0 0 1 0 0 0] as feedback. Since DL CC #3 is a deactivated DL CC,ACK/NACK bit corresponding to d0 and d1 is mapped to [0 0]. Also, sinceDL CC #2 transmits only one codeword, c1, which is ACK/NACK bit for asecond codeword of DL CC #2, is also mapped to 0. Similarly, since abase station already knows that DL CC #2 does not have a secondcodeword, c1 can be deduced from c0 for mapping. For example, if it isassumed that c1 is mapped by repeating c0, a UE can provide [1 1 0 0 1 10 0] as feedback. Since the base station already knows that ACK/NACK bitof c1, d0, and d1 has not been scheduled, decoding can be carried out byexcluding c1, d0, and d1 at the time of decoding feedback information.Also, if a codebook is [a0 a1 b0 b2 c0 d0 d1], the UE provide [1 1 0 0 10 0] as feedback.

FIG. 29 is a block diagram of a base station and a terminal for which anembodiment of the present invention is implemented.

A base station 800 comprises a processor 810, memory 820, and a radiofrequency (RF) unit 830. The processor 810 implements functions,procedures, and/or method according to the present invention. Layers ofwireless interface protocol can be implemented by the processor 810. Thememory 820, being connected to the processor 810, stores various kindsof information for activating the processor 810. The RF unit 830, beingconnected to the processor 810, transmits and/or receives wirelesssignals.

A UE 900 comprises a processor 910, memory 920, and an RF unit 930. Theprocessor 910 implements functions, procedures, and/or method accordingto the present invention. Layers of wireless interface protocol can beimplemented by the processor 910. The processor 910 performs channelcoding on information bits of the UCI to generate encoding informationbits, modulates the generated encoding information bits to generatecomplex modulation symbols, and block-wise spreads the complexmodulation symbols to multiple SC-FDMA symbols on the basis of anorthogonal sequence. The memory 920, being connected to the processor910, stores various kinds of information for activating the processor910. The RF unit 930, being connected to the processor 910, transmitsand/or receives wireless signals and transmits the spread complexmodulation symbols to the base station.

The processors 810, 910 may include application-specific integratedcircuit (ASIC), other chipset, logic circuit and/or data processingdevice. The memories 820, 920 may include read-only memory (ROM), randomaccess memory (RAM), flash memory, memory card, storage medium and/orother storage device. The RF units 830, 930 may include basebandcircuitry to process radio frequency signals. When the embodiments areimplemented in software, the techniques described herein can beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The modules can be stored inmemories 820, 920 and executed by processors 810, 910. The memories 820,920 can be implemented within the processors 810, 910 or external to theprocessors 810, 910 in which case those can be communicatively coupledto the processors 810, 910 via various means as is known in the art. Inview of the exemplary systems described herein, methodologies that maybe implemented in accordance with the disclosed subject matter have beendescribed with reference to several flow diagrams. While for purposed ofsimplicity, the methodologies are shown and described as a series ofsteps or blocks, it is to be understood and appreciated that the claimedsubject matter is not limited by the order of the steps or blocks, assome steps may occur in different orders or concurrently with othersteps from what is depicted and described herein. Moreover, one skilledin the art would understand that the steps illustrated in the flowdiagram are not exclusive and other steps may be included or one or moreof the steps in the example flow diagram may be deleted withoutaffecting the scope and spirit of the present disclosure.

What has been described above includes examples of the various aspects.It is, of course, not possible to describe every conceivable combinationof components or methodologies for purposes of describing the variousaspects, but one of ordinary skill in the art may recognize that manyfurther combinations and permutations are possible. Accordingly, thesubject specification is intended to embrace all such alternations,modifications and variations that fall within the spirit and scope ofthe appended claims.

1-15. (canceled)
 16. A method for transmitting, by a user equipment(UE), uplink control information (UCI) on a physical uplink controlchannel (PUCCH) in a wireless communication system, the methodcomprising: performing channel coding on information bits of the UCI togenerate encoded information bits, wherein the information bits of theUCI include hybrid automatic repeat request acknowledgement (HARQ-ACK)information bits for serving cells, and wherein a number of informationbits of the UCI is determined based on a number of the serving cells anda number of codewords for each of the serving cells, which is based on atransmission mode of each of the serving cells; modulating the encodedinformation bits to generate modulation symbols; spreading themodulation symbols with an orthogonal sequence; and transmitting thespread modulation symbols to a base station on the PUCCH, wherein if atransmission mode of one serving cell, among the serving cells, is asingle codeword transmission mode, a number of the HARQ-ACK informationbits for the one serving cell is 1 bit, and wherein if the transmissionmode of one serving cell, among the serving cells, is not a singlecodeword transmission mode, a number of the HARQ-ACK information bitsfor the one serving cell is 2 bits.
 17. The method of claim 16, whereinthe single codeword transmission mode is one of transmission modes 1, 2,5, 6, and
 7. 18. The method of claim 16, wherein if the transmissionmode of the one serving cell is not the single codeword transmissionmode, one bit of the HARQ-ACK information bits for the one serving cellcorresponds to an HARQ-ACK information bit for a first codeword, andwherein the remaining bit of the HARQ-ACK information bits for the oneserving cell corresponds to an HARQ-ACK information bit for a secondcodeword.
 19. The method of claim 16, wherein the PUCCH uses a PUCCHformat
 3. 20. The method of claim 16, wherein the HARQ-ACK informationbit for a corresponding serving cell which fails to receive a physicaldownlink control channel (PDCCH) corresponds to a non-acknowledgement(NACK).
 21. A user equipment (UE) comprising: a memory; a radiofrequency (RF) unit; and a processor coupled to the memory and the RFunit, and configured to: perform channel coding on information bits ofthe UCI to generate encoded information bits, wherein the informationbits of the UCI include hybrid automatic repeat request acknowledgement(HARQ-ACK) information bits for serving cells, and wherein a number ofinformation bits of the UCI is determined based on a number of theserving cells and a number of codewords for each of the serving cells,which is based on a transmission mode of each of the serving cells;modulate the encoded information bits to generate modulation symbols;spread the modulation symbols with an orthogonal sequence; and controlthe RF unit to transmit the spread modulation symbols to a base stationon the PUCCH, wherein if a transmission mode of one serving cell, amongthe serving cells, is a single codeword transmission mode, a number ofthe HARQ-ACK information bits for the one serving cell is 1 bit, andwherein if the transmission mode of one serving cell, among the servingcells, is not a single codeword transmission mode, a number of theHARQ-ACK information bits for the one serving cell is 2 bits.
 22. The UEof claim 21, wherein the single codeword transmission mode is one oftransmission modes 1, 2, 5, 6, and
 7. 23. The UE of claim 21, wherein ifthe transmission mode of the one serving cell is not the single codewordtransmission mode, one bit of the HARQ-ACK information bits for the oneserving cell corresponds to an HARQ-ACK information bit for a firstcodeword, and wherein the remaining bit of the HARQ-ACK information bitsfor the one serving cell corresponds to an HARQ-ACK information bit fora second codeword.
 24. The UE of claim 21, wherein the PUCCH uses aPUCCH format
 3. 25. The UE of claim 21, wherein the HARQ-ACK informationbit for a corresponding serving cell which fails to receive a physicaldownlink control channel (PDCCH) corresponds to a non-acknowledgement(NACK).